Merge remote-tracking branch 'asoc/fix/component' into asoc-linus
[linux-2.6-microblaze.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_version++;
68         inode->i_mapping->a_ops = &ecryptfs_aops;
69
70         if (S_ISLNK(inode->i_mode))
71                 inode->i_op = &ecryptfs_symlink_iops;
72         else if (S_ISDIR(inode->i_mode))
73                 inode->i_op = &ecryptfs_dir_iops;
74         else
75                 inode->i_op = &ecryptfs_main_iops;
76
77         if (S_ISDIR(inode->i_mode))
78                 inode->i_fop = &ecryptfs_dir_fops;
79         else if (special_file(inode->i_mode))
80                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
81         else
82                 inode->i_fop = &ecryptfs_main_fops;
83
84         return 0;
85 }
86
87 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
88                                           struct super_block *sb)
89 {
90         struct inode *inode;
91
92         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
93                 return ERR_PTR(-EXDEV);
94         if (!igrab(lower_inode))
95                 return ERR_PTR(-ESTALE);
96         inode = iget5_locked(sb, (unsigned long)lower_inode,
97                              ecryptfs_inode_test, ecryptfs_inode_set,
98                              lower_inode);
99         if (!inode) {
100                 iput(lower_inode);
101                 return ERR_PTR(-EACCES);
102         }
103         if (!(inode->i_state & I_NEW))
104                 iput(lower_inode);
105
106         return inode;
107 }
108
109 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
110                                  struct super_block *sb)
111 {
112         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
113
114         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
115                 unlock_new_inode(inode);
116
117         return inode;
118 }
119
120 /**
121  * ecryptfs_interpose
122  * @lower_dentry: Existing dentry in the lower filesystem
123  * @dentry: ecryptfs' dentry
124  * @sb: ecryptfs's super_block
125  *
126  * Interposes upper and lower dentries.
127  *
128  * Returns zero on success; non-zero otherwise
129  */
130 static int ecryptfs_interpose(struct dentry *lower_dentry,
131                               struct dentry *dentry, struct super_block *sb)
132 {
133         struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
134
135         if (IS_ERR(inode))
136                 return PTR_ERR(inode);
137         d_instantiate(dentry, inode);
138
139         return 0;
140 }
141
142 static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
143                               struct inode *inode)
144 {
145         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
146         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
147         struct dentry *lower_dir_dentry;
148         int rc;
149
150         dget(lower_dentry);
151         lower_dir_dentry = lock_parent(lower_dentry);
152         rc = vfs_unlink(lower_dir_inode, lower_dentry, NULL);
153         if (rc) {
154                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
155                 goto out_unlock;
156         }
157         fsstack_copy_attr_times(dir, lower_dir_inode);
158         set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
159         inode->i_ctime = dir->i_ctime;
160         d_drop(dentry);
161 out_unlock:
162         unlock_dir(lower_dir_dentry);
163         dput(lower_dentry);
164         return rc;
165 }
166
167 /**
168  * ecryptfs_do_create
169  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
170  * @ecryptfs_dentry: New file's dentry in ecryptfs
171  * @mode: The mode of the new file
172  *
173  * Creates the underlying file and the eCryptfs inode which will link to
174  * it. It will also update the eCryptfs directory inode to mimic the
175  * stat of the lower directory inode.
176  *
177  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
178  */
179 static struct inode *
180 ecryptfs_do_create(struct inode *directory_inode,
181                    struct dentry *ecryptfs_dentry, umode_t mode)
182 {
183         int rc;
184         struct dentry *lower_dentry;
185         struct dentry *lower_dir_dentry;
186         struct inode *inode;
187
188         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
189         lower_dir_dentry = lock_parent(lower_dentry);
190         rc = vfs_create(d_inode(lower_dir_dentry), lower_dentry, mode, true);
191         if (rc) {
192                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
193                        "rc = [%d]\n", __func__, rc);
194                 inode = ERR_PTR(rc);
195                 goto out_lock;
196         }
197         inode = __ecryptfs_get_inode(d_inode(lower_dentry),
198                                      directory_inode->i_sb);
199         if (IS_ERR(inode)) {
200                 vfs_unlink(d_inode(lower_dir_dentry), lower_dentry, NULL);
201                 goto out_lock;
202         }
203         fsstack_copy_attr_times(directory_inode, d_inode(lower_dir_dentry));
204         fsstack_copy_inode_size(directory_inode, d_inode(lower_dir_dentry));
205 out_lock:
206         unlock_dir(lower_dir_dentry);
207         return inode;
208 }
209
210 /**
211  * ecryptfs_initialize_file
212  *
213  * Cause the file to be changed from a basic empty file to an ecryptfs
214  * file with a header and first data page.
215  *
216  * Returns zero on success
217  */
218 int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
219                              struct inode *ecryptfs_inode)
220 {
221         struct ecryptfs_crypt_stat *crypt_stat =
222                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
223         int rc = 0;
224
225         if (S_ISDIR(ecryptfs_inode->i_mode)) {
226                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
227                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
228                 goto out;
229         }
230         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
231         rc = ecryptfs_new_file_context(ecryptfs_inode);
232         if (rc) {
233                 ecryptfs_printk(KERN_ERR, "Error creating new file "
234                                 "context; rc = [%d]\n", rc);
235                 goto out;
236         }
237         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
238         if (rc) {
239                 printk(KERN_ERR "%s: Error attempting to initialize "
240                         "the lower file for the dentry with name "
241                         "[%pd]; rc = [%d]\n", __func__,
242                         ecryptfs_dentry, rc);
243                 goto out;
244         }
245         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
246         if (rc)
247                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
248         ecryptfs_put_lower_file(ecryptfs_inode);
249 out:
250         return rc;
251 }
252
253 /**
254  * ecryptfs_create
255  * @dir: The inode of the directory in which to create the file.
256  * @dentry: The eCryptfs dentry
257  * @mode: The mode of the new file.
258  *
259  * Creates a new file.
260  *
261  * Returns zero on success; non-zero on error condition
262  */
263 static int
264 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
265                 umode_t mode, bool excl)
266 {
267         struct inode *ecryptfs_inode;
268         int rc;
269
270         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
271                                             mode);
272         if (IS_ERR(ecryptfs_inode)) {
273                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
274                                 "lower filesystem\n");
275                 rc = PTR_ERR(ecryptfs_inode);
276                 goto out;
277         }
278         /* At this point, a file exists on "disk"; we need to make sure
279          * that this on disk file is prepared to be an ecryptfs file */
280         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
281         if (rc) {
282                 ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
283                                    ecryptfs_inode);
284                 iget_failed(ecryptfs_inode);
285                 goto out;
286         }
287         unlock_new_inode(ecryptfs_inode);
288         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
289 out:
290         return rc;
291 }
292
293 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
294 {
295         struct ecryptfs_crypt_stat *crypt_stat;
296         int rc;
297
298         rc = ecryptfs_get_lower_file(dentry, inode);
299         if (rc) {
300                 printk(KERN_ERR "%s: Error attempting to initialize "
301                         "the lower file for the dentry with name "
302                         "[%pd]; rc = [%d]\n", __func__,
303                         dentry, rc);
304                 return rc;
305         }
306
307         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
308         /* TODO: lock for crypt_stat comparison */
309         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
310                 ecryptfs_set_default_sizes(crypt_stat);
311
312         rc = ecryptfs_read_and_validate_header_region(inode);
313         ecryptfs_put_lower_file(inode);
314         if (rc) {
315                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
316                 if (!rc)
317                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
318         }
319
320         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
321         return 0;
322 }
323
324 /**
325  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
326  */
327 static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
328                                      struct dentry *lower_dentry)
329 {
330         struct inode *inode, *lower_inode = d_inode(lower_dentry);
331         struct ecryptfs_dentry_info *dentry_info;
332         struct vfsmount *lower_mnt;
333         int rc = 0;
334
335         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
336         if (!dentry_info) {
337                 printk(KERN_ERR "%s: Out of memory whilst attempting "
338                        "to allocate ecryptfs_dentry_info struct\n",
339                         __func__);
340                 dput(lower_dentry);
341                 return ERR_PTR(-ENOMEM);
342         }
343
344         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
345         fsstack_copy_attr_atime(d_inode(dentry->d_parent),
346                                 d_inode(lower_dentry->d_parent));
347         BUG_ON(!d_count(lower_dentry));
348
349         ecryptfs_set_dentry_private(dentry, dentry_info);
350         dentry_info->lower_path.mnt = lower_mnt;
351         dentry_info->lower_path.dentry = lower_dentry;
352
353         if (d_really_is_negative(lower_dentry)) {
354                 /* We want to add because we couldn't find in lower */
355                 d_add(dentry, NULL);
356                 return NULL;
357         }
358         inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
359         if (IS_ERR(inode)) {
360                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
361                        __func__, PTR_ERR(inode));
362                 return ERR_CAST(inode);
363         }
364         if (S_ISREG(inode->i_mode)) {
365                 rc = ecryptfs_i_size_read(dentry, inode);
366                 if (rc) {
367                         make_bad_inode(inode);
368                         return ERR_PTR(rc);
369                 }
370         }
371
372         if (inode->i_state & I_NEW)
373                 unlock_new_inode(inode);
374         return d_splice_alias(inode, dentry);
375 }
376
377 /**
378  * ecryptfs_lookup
379  * @ecryptfs_dir_inode: The eCryptfs directory inode
380  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
381  * @flags: lookup flags
382  *
383  * Find a file on disk. If the file does not exist, then we'll add it to the
384  * dentry cache and continue on to read it from the disk.
385  */
386 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
387                                       struct dentry *ecryptfs_dentry,
388                                       unsigned int flags)
389 {
390         char *encrypted_and_encoded_name = NULL;
391         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
392         struct dentry *lower_dir_dentry, *lower_dentry;
393         const char *name = ecryptfs_dentry->d_name.name;
394         size_t len = ecryptfs_dentry->d_name.len;
395         struct dentry *res;
396         int rc = 0;
397
398         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
399
400         mount_crypt_stat = &ecryptfs_superblock_to_private(
401                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
402         if (mount_crypt_stat
403             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
404                 rc = ecryptfs_encrypt_and_encode_filename(
405                         &encrypted_and_encoded_name, &len,
406                         mount_crypt_stat, name, len);
407                 if (rc) {
408                         printk(KERN_ERR "%s: Error attempting to encrypt and encode "
409                                "filename; rc = [%d]\n", __func__, rc);
410                         return ERR_PTR(rc);
411                 }
412                 name = encrypted_and_encoded_name;
413         }
414
415         lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
416         if (IS_ERR(lower_dentry)) {
417                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
418                                 "[%ld] on lower_dentry = [%s]\n", __func__,
419                                 PTR_ERR(lower_dentry),
420                                 name);
421                 res = ERR_CAST(lower_dentry);
422         } else {
423                 res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
424         }
425         kfree(encrypted_and_encoded_name);
426         return res;
427 }
428
429 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
430                          struct dentry *new_dentry)
431 {
432         struct dentry *lower_old_dentry;
433         struct dentry *lower_new_dentry;
434         struct dentry *lower_dir_dentry;
435         u64 file_size_save;
436         int rc;
437
438         file_size_save = i_size_read(d_inode(old_dentry));
439         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
440         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
441         dget(lower_old_dentry);
442         dget(lower_new_dentry);
443         lower_dir_dentry = lock_parent(lower_new_dentry);
444         rc = vfs_link(lower_old_dentry, d_inode(lower_dir_dentry),
445                       lower_new_dentry, NULL);
446         if (rc || d_really_is_negative(lower_new_dentry))
447                 goto out_lock;
448         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
449         if (rc)
450                 goto out_lock;
451         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
452         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
453         set_nlink(d_inode(old_dentry),
454                   ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
455         i_size_write(d_inode(new_dentry), file_size_save);
456 out_lock:
457         unlock_dir(lower_dir_dentry);
458         dput(lower_new_dentry);
459         dput(lower_old_dentry);
460         return rc;
461 }
462
463 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
464 {
465         return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
466 }
467
468 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
469                             const char *symname)
470 {
471         int rc;
472         struct dentry *lower_dentry;
473         struct dentry *lower_dir_dentry;
474         char *encoded_symname;
475         size_t encoded_symlen;
476         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
477
478         lower_dentry = ecryptfs_dentry_to_lower(dentry);
479         dget(lower_dentry);
480         lower_dir_dentry = lock_parent(lower_dentry);
481         mount_crypt_stat = &ecryptfs_superblock_to_private(
482                 dir->i_sb)->mount_crypt_stat;
483         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
484                                                   &encoded_symlen,
485                                                   mount_crypt_stat, symname,
486                                                   strlen(symname));
487         if (rc)
488                 goto out_lock;
489         rc = vfs_symlink(d_inode(lower_dir_dentry), lower_dentry,
490                          encoded_symname);
491         kfree(encoded_symname);
492         if (rc || d_really_is_negative(lower_dentry))
493                 goto out_lock;
494         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
495         if (rc)
496                 goto out_lock;
497         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
498         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
499 out_lock:
500         unlock_dir(lower_dir_dentry);
501         dput(lower_dentry);
502         if (d_really_is_negative(dentry))
503                 d_drop(dentry);
504         return rc;
505 }
506
507 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
508 {
509         int rc;
510         struct dentry *lower_dentry;
511         struct dentry *lower_dir_dentry;
512
513         lower_dentry = ecryptfs_dentry_to_lower(dentry);
514         lower_dir_dentry = lock_parent(lower_dentry);
515         rc = vfs_mkdir(d_inode(lower_dir_dentry), lower_dentry, mode);
516         if (rc || d_really_is_negative(lower_dentry))
517                 goto out;
518         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
519         if (rc)
520                 goto out;
521         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
522         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
523         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
524 out:
525         unlock_dir(lower_dir_dentry);
526         if (d_really_is_negative(dentry))
527                 d_drop(dentry);
528         return rc;
529 }
530
531 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
532 {
533         struct dentry *lower_dentry;
534         struct dentry *lower_dir_dentry;
535         int rc;
536
537         lower_dentry = ecryptfs_dentry_to_lower(dentry);
538         dget(dentry);
539         lower_dir_dentry = lock_parent(lower_dentry);
540         dget(lower_dentry);
541         rc = vfs_rmdir(d_inode(lower_dir_dentry), lower_dentry);
542         dput(lower_dentry);
543         if (!rc && d_really_is_positive(dentry))
544                 clear_nlink(d_inode(dentry));
545         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
546         set_nlink(dir, d_inode(lower_dir_dentry)->i_nlink);
547         unlock_dir(lower_dir_dentry);
548         if (!rc)
549                 d_drop(dentry);
550         dput(dentry);
551         return rc;
552 }
553
554 static int
555 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
556 {
557         int rc;
558         struct dentry *lower_dentry;
559         struct dentry *lower_dir_dentry;
560
561         lower_dentry = ecryptfs_dentry_to_lower(dentry);
562         lower_dir_dentry = lock_parent(lower_dentry);
563         rc = vfs_mknod(d_inode(lower_dir_dentry), lower_dentry, mode, dev);
564         if (rc || d_really_is_negative(lower_dentry))
565                 goto out;
566         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
567         if (rc)
568                 goto out;
569         fsstack_copy_attr_times(dir, d_inode(lower_dir_dentry));
570         fsstack_copy_inode_size(dir, d_inode(lower_dir_dentry));
571 out:
572         unlock_dir(lower_dir_dentry);
573         if (d_really_is_negative(dentry))
574                 d_drop(dentry);
575         return rc;
576 }
577
578 static int
579 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
580                 struct inode *new_dir, struct dentry *new_dentry,
581                 unsigned int flags)
582 {
583         int rc;
584         struct dentry *lower_old_dentry;
585         struct dentry *lower_new_dentry;
586         struct dentry *lower_old_dir_dentry;
587         struct dentry *lower_new_dir_dentry;
588         struct dentry *trap = NULL;
589         struct inode *target_inode;
590
591         if (flags)
592                 return -EINVAL;
593
594         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
595         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
596         dget(lower_old_dentry);
597         dget(lower_new_dentry);
598         lower_old_dir_dentry = dget_parent(lower_old_dentry);
599         lower_new_dir_dentry = dget_parent(lower_new_dentry);
600         target_inode = d_inode(new_dentry);
601         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
602         /* source should not be ancestor of target */
603         if (trap == lower_old_dentry) {
604                 rc = -EINVAL;
605                 goto out_lock;
606         }
607         /* target should not be ancestor of source */
608         if (trap == lower_new_dentry) {
609                 rc = -ENOTEMPTY;
610                 goto out_lock;
611         }
612         rc = vfs_rename(d_inode(lower_old_dir_dentry), lower_old_dentry,
613                         d_inode(lower_new_dir_dentry), lower_new_dentry,
614                         NULL, 0);
615         if (rc)
616                 goto out_lock;
617         if (target_inode)
618                 fsstack_copy_attr_all(target_inode,
619                                       ecryptfs_inode_to_lower(target_inode));
620         fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
621         if (new_dir != old_dir)
622                 fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
623 out_lock:
624         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
625         dput(lower_new_dir_dentry);
626         dput(lower_old_dir_dentry);
627         dput(lower_new_dentry);
628         dput(lower_old_dentry);
629         return rc;
630 }
631
632 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
633 {
634         DEFINE_DELAYED_CALL(done);
635         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
636         const char *link;
637         char *buf;
638         int rc;
639
640         link = vfs_get_link(lower_dentry, &done);
641         if (IS_ERR(link))
642                 return ERR_CAST(link);
643
644         rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
645                                                   link, strlen(link));
646         do_delayed_call(&done);
647         if (rc)
648                 return ERR_PTR(rc);
649
650         return buf;
651 }
652
653 static const char *ecryptfs_get_link(struct dentry *dentry,
654                                      struct inode *inode,
655                                      struct delayed_call *done)
656 {
657         size_t len;
658         char *buf;
659
660         if (!dentry)
661                 return ERR_PTR(-ECHILD);
662
663         buf = ecryptfs_readlink_lower(dentry, &len);
664         if (IS_ERR(buf))
665                 return buf;
666         fsstack_copy_attr_atime(d_inode(dentry),
667                                 d_inode(ecryptfs_dentry_to_lower(dentry)));
668         buf[len] = '\0';
669         set_delayed_call(done, kfree_link, buf);
670         return buf;
671 }
672
673 /**
674  * upper_size_to_lower_size
675  * @crypt_stat: Crypt_stat associated with file
676  * @upper_size: Size of the upper file
677  *
678  * Calculate the required size of the lower file based on the
679  * specified size of the upper file. This calculation is based on the
680  * number of headers in the underlying file and the extent size.
681  *
682  * Returns Calculated size of the lower file.
683  */
684 static loff_t
685 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
686                          loff_t upper_size)
687 {
688         loff_t lower_size;
689
690         lower_size = ecryptfs_lower_header_size(crypt_stat);
691         if (upper_size != 0) {
692                 loff_t num_extents;
693
694                 num_extents = upper_size >> crypt_stat->extent_shift;
695                 if (upper_size & ~crypt_stat->extent_mask)
696                         num_extents++;
697                 lower_size += (num_extents * crypt_stat->extent_size);
698         }
699         return lower_size;
700 }
701
702 /**
703  * truncate_upper
704  * @dentry: The ecryptfs layer dentry
705  * @ia: Address of the ecryptfs inode's attributes
706  * @lower_ia: Address of the lower inode's attributes
707  *
708  * Function to handle truncations modifying the size of the file. Note
709  * that the file sizes are interpolated. When expanding, we are simply
710  * writing strings of 0's out. When truncating, we truncate the upper
711  * inode and update the lower_ia according to the page index
712  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
713  * the caller must use lower_ia in a call to notify_change() to perform
714  * the truncation of the lower inode.
715  *
716  * Returns zero on success; non-zero otherwise
717  */
718 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
719                           struct iattr *lower_ia)
720 {
721         int rc = 0;
722         struct inode *inode = d_inode(dentry);
723         struct ecryptfs_crypt_stat *crypt_stat;
724         loff_t i_size = i_size_read(inode);
725         loff_t lower_size_before_truncate;
726         loff_t lower_size_after_truncate;
727
728         if (unlikely((ia->ia_size == i_size))) {
729                 lower_ia->ia_valid &= ~ATTR_SIZE;
730                 return 0;
731         }
732         rc = ecryptfs_get_lower_file(dentry, inode);
733         if (rc)
734                 return rc;
735         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
736         /* Switch on growing or shrinking file */
737         if (ia->ia_size > i_size) {
738                 char zero[] = { 0x00 };
739
740                 lower_ia->ia_valid &= ~ATTR_SIZE;
741                 /* Write a single 0 at the last position of the file;
742                  * this triggers code that will fill in 0's throughout
743                  * the intermediate portion of the previous end of the
744                  * file and the new and of the file */
745                 rc = ecryptfs_write(inode, zero,
746                                     (ia->ia_size - 1), 1);
747         } else { /* ia->ia_size < i_size_read(inode) */
748                 /* We're chopping off all the pages down to the page
749                  * in which ia->ia_size is located. Fill in the end of
750                  * that page from (ia->ia_size & ~PAGE_MASK) to
751                  * PAGE_SIZE with zeros. */
752                 size_t num_zeros = (PAGE_SIZE
753                                     - (ia->ia_size & ~PAGE_MASK));
754
755                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
756                         truncate_setsize(inode, ia->ia_size);
757                         lower_ia->ia_size = ia->ia_size;
758                         lower_ia->ia_valid |= ATTR_SIZE;
759                         goto out;
760                 }
761                 if (num_zeros) {
762                         char *zeros_virt;
763
764                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
765                         if (!zeros_virt) {
766                                 rc = -ENOMEM;
767                                 goto out;
768                         }
769                         rc = ecryptfs_write(inode, zeros_virt,
770                                             ia->ia_size, num_zeros);
771                         kfree(zeros_virt);
772                         if (rc) {
773                                 printk(KERN_ERR "Error attempting to zero out "
774                                        "the remainder of the end page on "
775                                        "reducing truncate; rc = [%d]\n", rc);
776                                 goto out;
777                         }
778                 }
779                 truncate_setsize(inode, ia->ia_size);
780                 rc = ecryptfs_write_inode_size_to_metadata(inode);
781                 if (rc) {
782                         printk(KERN_ERR "Problem with "
783                                "ecryptfs_write_inode_size_to_metadata; "
784                                "rc = [%d]\n", rc);
785                         goto out;
786                 }
787                 /* We are reducing the size of the ecryptfs file, and need to
788                  * know if we need to reduce the size of the lower file. */
789                 lower_size_before_truncate =
790                     upper_size_to_lower_size(crypt_stat, i_size);
791                 lower_size_after_truncate =
792                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
793                 if (lower_size_after_truncate < lower_size_before_truncate) {
794                         lower_ia->ia_size = lower_size_after_truncate;
795                         lower_ia->ia_valid |= ATTR_SIZE;
796                 } else
797                         lower_ia->ia_valid &= ~ATTR_SIZE;
798         }
799 out:
800         ecryptfs_put_lower_file(inode);
801         return rc;
802 }
803
804 static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
805 {
806         struct ecryptfs_crypt_stat *crypt_stat;
807         loff_t lower_oldsize, lower_newsize;
808
809         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
810         lower_oldsize = upper_size_to_lower_size(crypt_stat,
811                                                  i_size_read(inode));
812         lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
813         if (lower_newsize > lower_oldsize) {
814                 /*
815                  * The eCryptfs inode and the new *lower* size are mixed here
816                  * because we may not have the lower i_mutex held and/or it may
817                  * not be appropriate to call inode_newsize_ok() with inodes
818                  * from other filesystems.
819                  */
820                 return inode_newsize_ok(inode, lower_newsize);
821         }
822
823         return 0;
824 }
825
826 /**
827  * ecryptfs_truncate
828  * @dentry: The ecryptfs layer dentry
829  * @new_length: The length to expand the file to
830  *
831  * Simple function that handles the truncation of an eCryptfs inode and
832  * its corresponding lower inode.
833  *
834  * Returns zero on success; non-zero otherwise
835  */
836 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
837 {
838         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
839         struct iattr lower_ia = { .ia_valid = 0 };
840         int rc;
841
842         rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
843         if (rc)
844                 return rc;
845
846         rc = truncate_upper(dentry, &ia, &lower_ia);
847         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
848                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
849
850                 inode_lock(d_inode(lower_dentry));
851                 rc = notify_change(lower_dentry, &lower_ia, NULL);
852                 inode_unlock(d_inode(lower_dentry));
853         }
854         return rc;
855 }
856
857 static int
858 ecryptfs_permission(struct inode *inode, int mask)
859 {
860         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
861 }
862
863 /**
864  * ecryptfs_setattr
865  * @dentry: dentry handle to the inode to modify
866  * @ia: Structure with flags of what to change and values
867  *
868  * Updates the metadata of an inode. If the update is to the size
869  * i.e. truncation, then ecryptfs_truncate will handle the size modification
870  * of both the ecryptfs inode and the lower inode.
871  *
872  * All other metadata changes will be passed right to the lower filesystem,
873  * and we will just update our inode to look like the lower.
874  */
875 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
876 {
877         int rc = 0;
878         struct dentry *lower_dentry;
879         struct iattr lower_ia;
880         struct inode *inode;
881         struct inode *lower_inode;
882         struct ecryptfs_crypt_stat *crypt_stat;
883
884         crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
885         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
886                 rc = ecryptfs_init_crypt_stat(crypt_stat);
887                 if (rc)
888                         return rc;
889         }
890         inode = d_inode(dentry);
891         lower_inode = ecryptfs_inode_to_lower(inode);
892         lower_dentry = ecryptfs_dentry_to_lower(dentry);
893         mutex_lock(&crypt_stat->cs_mutex);
894         if (d_is_dir(dentry))
895                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
896         else if (d_is_reg(dentry)
897                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
898                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
899                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
900
901                 mount_crypt_stat = &ecryptfs_superblock_to_private(
902                         dentry->d_sb)->mount_crypt_stat;
903                 rc = ecryptfs_get_lower_file(dentry, inode);
904                 if (rc) {
905                         mutex_unlock(&crypt_stat->cs_mutex);
906                         goto out;
907                 }
908                 rc = ecryptfs_read_metadata(dentry);
909                 ecryptfs_put_lower_file(inode);
910                 if (rc) {
911                         if (!(mount_crypt_stat->flags
912                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
913                                 rc = -EIO;
914                                 printk(KERN_WARNING "Either the lower file "
915                                        "is not in a valid eCryptfs format, "
916                                        "or the key could not be retrieved. "
917                                        "Plaintext passthrough mode is not "
918                                        "enabled; returning -EIO\n");
919                                 mutex_unlock(&crypt_stat->cs_mutex);
920                                 goto out;
921                         }
922                         rc = 0;
923                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
924                                                | ECRYPTFS_ENCRYPTED);
925                 }
926         }
927         mutex_unlock(&crypt_stat->cs_mutex);
928
929         rc = setattr_prepare(dentry, ia);
930         if (rc)
931                 goto out;
932         if (ia->ia_valid & ATTR_SIZE) {
933                 rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
934                 if (rc)
935                         goto out;
936         }
937
938         memcpy(&lower_ia, ia, sizeof(lower_ia));
939         if (ia->ia_valid & ATTR_FILE)
940                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
941         if (ia->ia_valid & ATTR_SIZE) {
942                 rc = truncate_upper(dentry, ia, &lower_ia);
943                 if (rc < 0)
944                         goto out;
945         }
946
947         /*
948          * mode change is for clearing setuid/setgid bits. Allow lower fs
949          * to interpret this in its own way.
950          */
951         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
952                 lower_ia.ia_valid &= ~ATTR_MODE;
953
954         inode_lock(d_inode(lower_dentry));
955         rc = notify_change(lower_dentry, &lower_ia, NULL);
956         inode_unlock(d_inode(lower_dentry));
957 out:
958         fsstack_copy_attr_all(inode, lower_inode);
959         return rc;
960 }
961
962 static int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
963                                  struct kstat *stat)
964 {
965         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
966         int rc = 0;
967
968         mount_crypt_stat = &ecryptfs_superblock_to_private(
969                                                 dentry->d_sb)->mount_crypt_stat;
970         generic_fillattr(d_inode(dentry), stat);
971         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
972                 char *target;
973                 size_t targetsiz;
974
975                 target = ecryptfs_readlink_lower(dentry, &targetsiz);
976                 if (!IS_ERR(target)) {
977                         kfree(target);
978                         stat->size = targetsiz;
979                 } else {
980                         rc = PTR_ERR(target);
981                 }
982         }
983         return rc;
984 }
985
986 static int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
987                             struct kstat *stat)
988 {
989         struct kstat lower_stat;
990         int rc;
991
992         rc = vfs_getattr(ecryptfs_dentry_to_lower_path(dentry), &lower_stat);
993         if (!rc) {
994                 fsstack_copy_attr_all(d_inode(dentry),
995                                       ecryptfs_inode_to_lower(d_inode(dentry)));
996                 generic_fillattr(d_inode(dentry), stat);
997                 stat->blocks = lower_stat.blocks;
998         }
999         return rc;
1000 }
1001
1002 int
1003 ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
1004                   const char *name, const void *value,
1005                   size_t size, int flags)
1006 {
1007         int rc;
1008         struct dentry *lower_dentry;
1009
1010         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1011         if (!(d_inode(lower_dentry)->i_opflags & IOP_XATTR)) {
1012                 rc = -EOPNOTSUPP;
1013                 goto out;
1014         }
1015         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1016         if (!rc && inode)
1017                 fsstack_copy_attr_all(inode, d_inode(lower_dentry));
1018 out:
1019         return rc;
1020 }
1021
1022 ssize_t
1023 ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
1024                         const char *name, void *value, size_t size)
1025 {
1026         int rc;
1027
1028         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1029                 rc = -EOPNOTSUPP;
1030                 goto out;
1031         }
1032         inode_lock(lower_inode);
1033         rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
1034         inode_unlock(lower_inode);
1035 out:
1036         return rc;
1037 }
1038
1039 static ssize_t
1040 ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
1041                   const char *name, void *value, size_t size)
1042 {
1043         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1044                                        ecryptfs_inode_to_lower(inode),
1045                                        name, value, size);
1046 }
1047
1048 static ssize_t
1049 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1050 {
1051         int rc = 0;
1052         struct dentry *lower_dentry;
1053
1054         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1055         if (!d_inode(lower_dentry)->i_op->listxattr) {
1056                 rc = -EOPNOTSUPP;
1057                 goto out;
1058         }
1059         inode_lock(d_inode(lower_dentry));
1060         rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
1061         inode_unlock(d_inode(lower_dentry));
1062 out:
1063         return rc;
1064 }
1065
1066 static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
1067                                 const char *name)
1068 {
1069         int rc;
1070         struct dentry *lower_dentry;
1071         struct inode *lower_inode;
1072
1073         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1074         lower_inode = ecryptfs_inode_to_lower(inode);
1075         if (!(lower_inode->i_opflags & IOP_XATTR)) {
1076                 rc = -EOPNOTSUPP;
1077                 goto out;
1078         }
1079         inode_lock(lower_inode);
1080         rc = __vfs_removexattr(lower_dentry, name);
1081         inode_unlock(lower_inode);
1082 out:
1083         return rc;
1084 }
1085
1086 const struct inode_operations ecryptfs_symlink_iops = {
1087         .get_link = ecryptfs_get_link,
1088         .permission = ecryptfs_permission,
1089         .setattr = ecryptfs_setattr,
1090         .getattr = ecryptfs_getattr_link,
1091         .listxattr = ecryptfs_listxattr,
1092 };
1093
1094 const struct inode_operations ecryptfs_dir_iops = {
1095         .create = ecryptfs_create,
1096         .lookup = ecryptfs_lookup,
1097         .link = ecryptfs_link,
1098         .unlink = ecryptfs_unlink,
1099         .symlink = ecryptfs_symlink,
1100         .mkdir = ecryptfs_mkdir,
1101         .rmdir = ecryptfs_rmdir,
1102         .mknod = ecryptfs_mknod,
1103         .rename = ecryptfs_rename,
1104         .permission = ecryptfs_permission,
1105         .setattr = ecryptfs_setattr,
1106         .listxattr = ecryptfs_listxattr,
1107 };
1108
1109 const struct inode_operations ecryptfs_main_iops = {
1110         .permission = ecryptfs_permission,
1111         .setattr = ecryptfs_setattr,
1112         .getattr = ecryptfs_getattr,
1113         .listxattr = ecryptfs_listxattr,
1114 };
1115
1116 static int ecryptfs_xattr_get(const struct xattr_handler *handler,
1117                               struct dentry *dentry, struct inode *inode,
1118                               const char *name, void *buffer, size_t size)
1119 {
1120         return ecryptfs_getxattr(dentry, inode, name, buffer, size);
1121 }
1122
1123 static int ecryptfs_xattr_set(const struct xattr_handler *handler,
1124                               struct dentry *dentry, struct inode *inode,
1125                               const char *name, const void *value, size_t size,
1126                               int flags)
1127 {
1128         if (value)
1129                 return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
1130         else {
1131                 BUG_ON(flags != XATTR_REPLACE);
1132                 return ecryptfs_removexattr(dentry, inode, name);
1133         }
1134 }
1135
1136 const struct xattr_handler ecryptfs_xattr_handler = {
1137         .prefix = "",  /* match anything */
1138         .get = ecryptfs_xattr_get,
1139         .set = ecryptfs_xattr_set,
1140 };
1141
1142 const struct xattr_handler *ecryptfs_xattr_handlers[] = {
1143         &ecryptfs_xattr_handler,
1144         NULL
1145 };