Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland...
[pandora-kernel.git] / fs / ecryptfs / inode.c
1 /**
2  * eCryptfs: Linux filesystem encryption layer
3  *
4  * Copyright (C) 1997-2004 Erez Zadok
5  * Copyright (C) 2001-2004 Stony Brook University
6  * Copyright (C) 2004-2007 International Business Machines Corp.
7  *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
8  *              Michael C. Thompsion <mcthomps@us.ibm.com>
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public License as
12  * published by the Free Software Foundation; either version 2 of the
13  * License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23  * 02111-1307, USA.
24  */
25
26 #include <linux/file.h>
27 #include <linux/vmalloc.h>
28 #include <linux/pagemap.h>
29 #include <linux/dcache.h>
30 #include <linux/namei.h>
31 #include <linux/mount.h>
32 #include <linux/crypto.h>
33 #include <linux/fs_stack.h>
34 #include <linux/slab.h>
35 #include <linux/xattr.h>
36 #include <asm/unaligned.h>
37 #include "ecryptfs_kernel.h"
38
39 static struct dentry *lock_parent(struct dentry *dentry)
40 {
41         struct dentry *dir;
42
43         dir = dget_parent(dentry);
44         mutex_lock_nested(&(dir->d_inode->i_mutex), I_MUTEX_PARENT);
45         return dir;
46 }
47
48 static void unlock_dir(struct dentry *dir)
49 {
50         mutex_unlock(&dir->d_inode->i_mutex);
51         dput(dir);
52 }
53
54 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
55 {
56         if (ecryptfs_inode_to_lower(inode) == (struct inode *)lower_inode)
57                 return 1;
58         return 0;
59 }
60
61 static int ecryptfs_inode_set(struct inode *inode, void *opaque)
62 {
63         struct inode *lower_inode = opaque;
64
65         ecryptfs_set_inode_lower(inode, lower_inode);
66         fsstack_copy_attr_all(inode, lower_inode);
67         /* i_size will be overwritten for encrypted regular files */
68         fsstack_copy_inode_size(inode, lower_inode);
69         inode->i_ino = lower_inode->i_ino;
70         inode->i_version++;
71         inode->i_mapping->a_ops = &ecryptfs_aops;
72         inode->i_mapping->backing_dev_info = inode->i_sb->s_bdi;
73
74         if (S_ISLNK(inode->i_mode))
75                 inode->i_op = &ecryptfs_symlink_iops;
76         else if (S_ISDIR(inode->i_mode))
77                 inode->i_op = &ecryptfs_dir_iops;
78         else
79                 inode->i_op = &ecryptfs_main_iops;
80
81         if (S_ISDIR(inode->i_mode))
82                 inode->i_fop = &ecryptfs_dir_fops;
83         else if (special_file(inode->i_mode))
84                 init_special_inode(inode, inode->i_mode, inode->i_rdev);
85         else
86                 inode->i_fop = &ecryptfs_main_fops;
87
88         return 0;
89 }
90
91 static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
92                                           struct super_block *sb)
93 {
94         struct inode *inode;
95
96         if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
97                 return ERR_PTR(-EXDEV);
98         if (!igrab(lower_inode))
99                 return ERR_PTR(-ESTALE);
100         inode = iget5_locked(sb, (unsigned long)lower_inode,
101                              ecryptfs_inode_test, ecryptfs_inode_set,
102                              lower_inode);
103         if (!inode) {
104                 iput(lower_inode);
105                 return ERR_PTR(-EACCES);
106         }
107         if (!(inode->i_state & I_NEW))
108                 iput(lower_inode);
109
110         return inode;
111 }
112
113 struct inode *ecryptfs_get_inode(struct inode *lower_inode,
114                                  struct super_block *sb)
115 {
116         struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
117
118         if (!IS_ERR(inode) && (inode->i_state & I_NEW))
119                 unlock_new_inode(inode);
120
121         return inode;
122 }
123
124 /**
125  * ecryptfs_interpose
126  * @lower_dentry: Existing dentry in the lower filesystem
127  * @dentry: ecryptfs' dentry
128  * @sb: ecryptfs's super_block
129  *
130  * Interposes upper and lower dentries.
131  *
132  * Returns zero on success; non-zero otherwise
133  */
134 static int ecryptfs_interpose(struct dentry *lower_dentry,
135                               struct dentry *dentry, struct super_block *sb)
136 {
137         struct inode *inode = ecryptfs_get_inode(lower_dentry->d_inode, sb);
138
139         if (IS_ERR(inode))
140                 return PTR_ERR(inode);
141         d_instantiate(dentry, inode);
142
143         return 0;
144 }
145
146 /**
147  * ecryptfs_create_underlying_file
148  * @lower_dir_inode: inode of the parent in the lower fs of the new file
149  * @dentry: New file's dentry
150  * @mode: The mode of the new file
151  *
152  * Creates the file in the lower file system.
153  *
154  * Returns zero on success; non-zero on error condition
155  */
156 static int
157 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
158                                 struct dentry *dentry, int mode)
159 {
160         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
161         return vfs_create(lower_dir_inode, lower_dentry, mode, NULL);
162 }
163
164 /**
165  * ecryptfs_do_create
166  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
167  * @ecryptfs_dentry: New file's dentry in ecryptfs
168  * @mode: The mode of the new file
169  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
170  *
171  * Creates the underlying file and the eCryptfs inode which will link to
172  * it. It will also update the eCryptfs directory inode to mimic the
173  * stat of the lower directory inode.
174  *
175  * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
176  */
177 static struct inode *
178 ecryptfs_do_create(struct inode *directory_inode,
179                    struct dentry *ecryptfs_dentry, int mode)
180 {
181         int rc;
182         struct dentry *lower_dentry;
183         struct dentry *lower_dir_dentry;
184         struct inode *inode;
185
186         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
187         lower_dir_dentry = lock_parent(lower_dentry);
188         if (IS_ERR(lower_dir_dentry)) {
189                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
190                                 "dentry\n");
191                 inode = ERR_CAST(lower_dir_dentry);
192                 goto out;
193         }
194         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
195                                              ecryptfs_dentry, mode);
196         if (rc) {
197                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
198                        "rc = [%d]\n", __func__, rc);
199                 inode = ERR_PTR(rc);
200                 goto out_lock;
201         }
202         inode = __ecryptfs_get_inode(lower_dentry->d_inode,
203                                      directory_inode->i_sb);
204         if (IS_ERR(inode))
205                 goto out_lock;
206         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
207         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
208 out_lock:
209         unlock_dir(lower_dir_dentry);
210 out:
211         return inode;
212 }
213
214 /**
215  * ecryptfs_initialize_file
216  *
217  * Cause the file to be changed from a basic empty file to an ecryptfs
218  * file with a header and first data page.
219  *
220  * Returns zero on success
221  */
222 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
223                                     struct inode *ecryptfs_inode)
224 {
225         struct ecryptfs_crypt_stat *crypt_stat =
226                 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
227         int rc = 0;
228
229         if (S_ISDIR(ecryptfs_inode->i_mode)) {
230                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
231                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
232                 goto out;
233         }
234         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
235         rc = ecryptfs_new_file_context(ecryptfs_inode);
236         if (rc) {
237                 ecryptfs_printk(KERN_ERR, "Error creating new file "
238                                 "context; rc = [%d]\n", rc);
239                 goto out;
240         }
241         rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
242         if (rc) {
243                 printk(KERN_ERR "%s: Error attempting to initialize "
244                         "the lower file for the dentry with name "
245                         "[%s]; rc = [%d]\n", __func__,
246                         ecryptfs_dentry->d_name.name, rc);
247                 goto out;
248         }
249         rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
250         if (rc)
251                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
252         ecryptfs_put_lower_file(ecryptfs_inode);
253 out:
254         return rc;
255 }
256
257 /**
258  * ecryptfs_create
259  * @dir: The inode of the directory in which to create the file.
260  * @dentry: The eCryptfs dentry
261  * @mode: The mode of the new file.
262  * @nd: nameidata
263  *
264  * Creates a new file.
265  *
266  * Returns zero on success; non-zero on error condition
267  */
268 static int
269 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
270                 int mode, struct nameidata *nd)
271 {
272         struct inode *ecryptfs_inode;
273         int rc;
274
275         ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
276                                             mode);
277         if (unlikely(IS_ERR(ecryptfs_inode))) {
278                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
279                                 "lower filesystem\n");
280                 rc = PTR_ERR(ecryptfs_inode);
281                 goto out;
282         }
283         /* At this point, a file exists on "disk"; we need to make sure
284          * that this on disk file is prepared to be an ecryptfs file */
285         rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
286         if (rc) {
287                 drop_nlink(ecryptfs_inode);
288                 unlock_new_inode(ecryptfs_inode);
289                 iput(ecryptfs_inode);
290                 goto out;
291         }
292         d_instantiate(ecryptfs_dentry, ecryptfs_inode);
293         unlock_new_inode(ecryptfs_inode);
294 out:
295         return rc;
296 }
297
298 static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
299 {
300         struct ecryptfs_crypt_stat *crypt_stat;
301         int rc;
302
303         rc = ecryptfs_get_lower_file(dentry, inode);
304         if (rc) {
305                 printk(KERN_ERR "%s: Error attempting to initialize "
306                         "the lower file for the dentry with name "
307                         "[%s]; rc = [%d]\n", __func__,
308                         dentry->d_name.name, rc);
309                 return rc;
310         }
311
312         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
313         /* TODO: lock for crypt_stat comparison */
314         if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
315                 ecryptfs_set_default_sizes(crypt_stat);
316
317         rc = ecryptfs_read_and_validate_header_region(inode);
318         ecryptfs_put_lower_file(inode);
319         if (rc) {
320                 rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
321                 if (!rc)
322                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
323         }
324
325         /* Must return 0 to allow non-eCryptfs files to be looked up, too */
326         return 0;
327 }
328
329 /**
330  * ecryptfs_lookup_interpose - Dentry interposition for a lookup
331  */
332 static int ecryptfs_lookup_interpose(struct dentry *dentry,
333                                      struct dentry *lower_dentry,
334                                      struct inode *dir_inode)
335 {
336         struct inode *inode, *lower_inode = lower_dentry->d_inode;
337         struct ecryptfs_dentry_info *dentry_info;
338         struct vfsmount *lower_mnt;
339         int rc = 0;
340
341         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(dentry->d_parent));
342         fsstack_copy_attr_atime(dir_inode, lower_dentry->d_parent->d_inode);
343         BUG_ON(!lower_dentry->d_count);
344
345         dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
346         ecryptfs_set_dentry_private(dentry, dentry_info);
347         if (!dentry_info) {
348                 printk(KERN_ERR "%s: Out of memory whilst attempting "
349                        "to allocate ecryptfs_dentry_info struct\n",
350                         __func__);
351                 dput(lower_dentry);
352                 mntput(lower_mnt);
353                 d_drop(dentry);
354                 return -ENOMEM;
355         }
356         ecryptfs_set_dentry_lower(dentry, lower_dentry);
357         ecryptfs_set_dentry_lower_mnt(dentry, lower_mnt);
358
359         if (!lower_dentry->d_inode) {
360                 /* We want to add because we couldn't find in lower */
361                 d_add(dentry, NULL);
362                 return 0;
363         }
364         inode = __ecryptfs_get_inode(lower_inode, dir_inode->i_sb);
365         if (IS_ERR(inode)) {
366                 printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
367                        __func__, PTR_ERR(inode));
368                 return PTR_ERR(inode);
369         }
370         if (S_ISREG(inode->i_mode)) {
371                 rc = ecryptfs_i_size_read(dentry, inode);
372                 if (rc) {
373                         make_bad_inode(inode);
374                         return rc;
375                 }
376         }
377
378         if (inode->i_state & I_NEW)
379                 unlock_new_inode(inode);
380         d_add(dentry, inode);
381
382         return rc;
383 }
384
385 /**
386  * ecryptfs_lookup
387  * @ecryptfs_dir_inode: The eCryptfs directory inode
388  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
389  * @ecryptfs_nd: nameidata; may be NULL
390  *
391  * Find a file on disk. If the file does not exist, then we'll add it to the
392  * dentry cache and continue on to read it from the disk.
393  */
394 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
395                                       struct dentry *ecryptfs_dentry,
396                                       struct nameidata *ecryptfs_nd)
397 {
398         char *encrypted_and_encoded_name = NULL;
399         size_t encrypted_and_encoded_name_size;
400         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
401         struct dentry *lower_dir_dentry, *lower_dentry;
402         int rc = 0;
403
404         if ((ecryptfs_dentry->d_name.len == 1
405              && !strcmp(ecryptfs_dentry->d_name.name, "."))
406             || (ecryptfs_dentry->d_name.len == 2
407                 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
408                 goto out_d_drop;
409         }
410         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
411         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
412         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
413                                       lower_dir_dentry,
414                                       ecryptfs_dentry->d_name.len);
415         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
416         if (IS_ERR(lower_dentry)) {
417                 rc = PTR_ERR(lower_dentry);
418                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
419                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
420                                 encrypted_and_encoded_name);
421                 goto out_d_drop;
422         }
423         if (lower_dentry->d_inode)
424                 goto interpose;
425         mount_crypt_stat = &ecryptfs_superblock_to_private(
426                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
427         if (!(mount_crypt_stat
428             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
429                 goto interpose;
430         dput(lower_dentry);
431         rc = ecryptfs_encrypt_and_encode_filename(
432                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
433                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
434                 ecryptfs_dentry->d_name.len);
435         if (rc) {
436                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
437                        "filename; rc = [%d]\n", __func__, rc);
438                 goto out_d_drop;
439         }
440         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
441         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
442                                       lower_dir_dentry,
443                                       encrypted_and_encoded_name_size);
444         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
445         if (IS_ERR(lower_dentry)) {
446                 rc = PTR_ERR(lower_dentry);
447                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
448                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
449                                 encrypted_and_encoded_name);
450                 goto out_d_drop;
451         }
452 interpose:
453         rc = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry,
454                                        ecryptfs_dir_inode);
455         goto out;
456 out_d_drop:
457         d_drop(ecryptfs_dentry);
458 out:
459         kfree(encrypted_and_encoded_name);
460         return ERR_PTR(rc);
461 }
462
463 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
464                          struct dentry *new_dentry)
465 {
466         struct dentry *lower_old_dentry;
467         struct dentry *lower_new_dentry;
468         struct dentry *lower_dir_dentry;
469         u64 file_size_save;
470         int rc;
471
472         file_size_save = i_size_read(old_dentry->d_inode);
473         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
474         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
475         dget(lower_old_dentry);
476         dget(lower_new_dentry);
477         lower_dir_dentry = lock_parent(lower_new_dentry);
478         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
479                       lower_new_dentry);
480         if (rc || !lower_new_dentry->d_inode)
481                 goto out_lock;
482         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
483         if (rc)
484                 goto out_lock;
485         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
486         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
487         set_nlink(old_dentry->d_inode,
488                   ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink);
489         i_size_write(new_dentry->d_inode, file_size_save);
490 out_lock:
491         unlock_dir(lower_dir_dentry);
492         dput(lower_new_dentry);
493         dput(lower_old_dentry);
494         return rc;
495 }
496
497 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
498 {
499         int rc = 0;
500         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
501         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
502         struct dentry *lower_dir_dentry;
503
504         dget(lower_dentry);
505         lower_dir_dentry = lock_parent(lower_dentry);
506         rc = vfs_unlink(lower_dir_inode, lower_dentry);
507         if (rc) {
508                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
509                 goto out_unlock;
510         }
511         fsstack_copy_attr_times(dir, lower_dir_inode);
512         set_nlink(dentry->d_inode,
513                   ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink);
514         dentry->d_inode->i_ctime = dir->i_ctime;
515         d_drop(dentry);
516 out_unlock:
517         unlock_dir(lower_dir_dentry);
518         dput(lower_dentry);
519         return rc;
520 }
521
522 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
523                             const char *symname)
524 {
525         int rc;
526         struct dentry *lower_dentry;
527         struct dentry *lower_dir_dentry;
528         char *encoded_symname;
529         size_t encoded_symlen;
530         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
531
532         lower_dentry = ecryptfs_dentry_to_lower(dentry);
533         dget(lower_dentry);
534         lower_dir_dentry = lock_parent(lower_dentry);
535         mount_crypt_stat = &ecryptfs_superblock_to_private(
536                 dir->i_sb)->mount_crypt_stat;
537         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
538                                                   &encoded_symlen,
539                                                   NULL,
540                                                   mount_crypt_stat, symname,
541                                                   strlen(symname));
542         if (rc)
543                 goto out_lock;
544         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
545                          encoded_symname);
546         kfree(encoded_symname);
547         if (rc || !lower_dentry->d_inode)
548                 goto out_lock;
549         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
550         if (rc)
551                 goto out_lock;
552         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
553         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
554 out_lock:
555         unlock_dir(lower_dir_dentry);
556         dput(lower_dentry);
557         if (!dentry->d_inode)
558                 d_drop(dentry);
559         return rc;
560 }
561
562 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
563 {
564         int rc;
565         struct dentry *lower_dentry;
566         struct dentry *lower_dir_dentry;
567
568         lower_dentry = ecryptfs_dentry_to_lower(dentry);
569         lower_dir_dentry = lock_parent(lower_dentry);
570         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
571         if (rc || !lower_dentry->d_inode)
572                 goto out;
573         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
574         if (rc)
575                 goto out;
576         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
577         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
578         set_nlink(dir, lower_dir_dentry->d_inode->i_nlink);
579 out:
580         unlock_dir(lower_dir_dentry);
581         if (!dentry->d_inode)
582                 d_drop(dentry);
583         return rc;
584 }
585
586 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
587 {
588         struct dentry *lower_dentry;
589         struct dentry *lower_dir_dentry;
590         int rc;
591
592         lower_dentry = ecryptfs_dentry_to_lower(dentry);
593         dget(dentry);
594         lower_dir_dentry = lock_parent(lower_dentry);
595         dget(lower_dentry);
596         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
597         dput(lower_dentry);
598         if (!rc && dentry->d_inode)
599                 clear_nlink(dentry->d_inode);
600         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
601         set_nlink(dir, lower_dir_dentry->d_inode->i_nlink);
602         unlock_dir(lower_dir_dentry);
603         if (!rc)
604                 d_drop(dentry);
605         dput(dentry);
606         return rc;
607 }
608
609 static int
610 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
611 {
612         int rc;
613         struct dentry *lower_dentry;
614         struct dentry *lower_dir_dentry;
615
616         lower_dentry = ecryptfs_dentry_to_lower(dentry);
617         lower_dir_dentry = lock_parent(lower_dentry);
618         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
619         if (rc || !lower_dentry->d_inode)
620                 goto out;
621         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
622         if (rc)
623                 goto out;
624         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
625         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
626 out:
627         unlock_dir(lower_dir_dentry);
628         if (!dentry->d_inode)
629                 d_drop(dentry);
630         return rc;
631 }
632
633 static int
634 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
635                 struct inode *new_dir, struct dentry *new_dentry)
636 {
637         int rc;
638         struct dentry *lower_old_dentry;
639         struct dentry *lower_new_dentry;
640         struct dentry *lower_old_dir_dentry;
641         struct dentry *lower_new_dir_dentry;
642         struct dentry *trap = NULL;
643
644         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
645         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
646         dget(lower_old_dentry);
647         dget(lower_new_dentry);
648         lower_old_dir_dentry = dget_parent(lower_old_dentry);
649         lower_new_dir_dentry = dget_parent(lower_new_dentry);
650         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
651         /* source should not be ancestor of target */
652         if (trap == lower_old_dentry) {
653                 rc = -EINVAL;
654                 goto out_lock;
655         }
656         /* target should not be ancestor of source */
657         if (trap == lower_new_dentry) {
658                 rc = -ENOTEMPTY;
659                 goto out_lock;
660         }
661         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
662                         lower_new_dir_dentry->d_inode, lower_new_dentry);
663         if (rc)
664                 goto out_lock;
665         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
666         if (new_dir != old_dir)
667                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
668 out_lock:
669         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
670         dput(lower_new_dir_dentry);
671         dput(lower_old_dir_dentry);
672         dput(lower_new_dentry);
673         dput(lower_old_dentry);
674         return rc;
675 }
676
677 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
678                                    size_t *bufsiz)
679 {
680         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
681         char *lower_buf;
682         size_t lower_bufsiz = PATH_MAX;
683         mm_segment_t old_fs;
684         int rc;
685
686         lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
687         if (!lower_buf) {
688                 rc = -ENOMEM;
689                 goto out;
690         }
691         old_fs = get_fs();
692         set_fs(get_ds());
693         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
694                                                    (char __user *)lower_buf,
695                                                    lower_bufsiz);
696         set_fs(old_fs);
697         if (rc < 0)
698                 goto out;
699         lower_bufsiz = rc;
700         rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
701                                                   lower_buf, lower_bufsiz);
702 out:
703         kfree(lower_buf);
704         return rc;
705 }
706
707 static int
708 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
709 {
710         char *kbuf;
711         size_t kbufsiz, copied;
712         int rc;
713
714         rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
715         if (rc)
716                 goto out;
717         copied = min_t(size_t, bufsiz, kbufsiz);
718         rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
719         kfree(kbuf);
720         fsstack_copy_attr_atime(dentry->d_inode,
721                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
722 out:
723         return rc;
724 }
725
726 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
727 {
728         char *buf;
729         int len = PAGE_SIZE, rc;
730         mm_segment_t old_fs;
731
732         /* Released in ecryptfs_put_link(); only release here on error */
733         buf = kmalloc(len, GFP_KERNEL);
734         if (!buf) {
735                 buf = ERR_PTR(-ENOMEM);
736                 goto out;
737         }
738         old_fs = get_fs();
739         set_fs(get_ds());
740         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
741         set_fs(old_fs);
742         if (rc < 0) {
743                 kfree(buf);
744                 buf = ERR_PTR(rc);
745         } else
746                 buf[rc] = '\0';
747 out:
748         nd_set_link(nd, buf);
749         return NULL;
750 }
751
752 static void
753 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
754 {
755         char *buf = nd_get_link(nd);
756         if (!IS_ERR(buf)) {
757                 /* Free the char* */
758                 kfree(buf);
759         }
760 }
761
762 /**
763  * upper_size_to_lower_size
764  * @crypt_stat: Crypt_stat associated with file
765  * @upper_size: Size of the upper file
766  *
767  * Calculate the required size of the lower file based on the
768  * specified size of the upper file. This calculation is based on the
769  * number of headers in the underlying file and the extent size.
770  *
771  * Returns Calculated size of the lower file.
772  */
773 static loff_t
774 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
775                          loff_t upper_size)
776 {
777         loff_t lower_size;
778
779         lower_size = ecryptfs_lower_header_size(crypt_stat);
780         if (upper_size != 0) {
781                 loff_t num_extents;
782
783                 num_extents = upper_size >> crypt_stat->extent_shift;
784                 if (upper_size & ~crypt_stat->extent_mask)
785                         num_extents++;
786                 lower_size += (num_extents * crypt_stat->extent_size);
787         }
788         return lower_size;
789 }
790
791 /**
792  * truncate_upper
793  * @dentry: The ecryptfs layer dentry
794  * @ia: Address of the ecryptfs inode's attributes
795  * @lower_ia: Address of the lower inode's attributes
796  *
797  * Function to handle truncations modifying the size of the file. Note
798  * that the file sizes are interpolated. When expanding, we are simply
799  * writing strings of 0's out. When truncating, we truncate the upper
800  * inode and update the lower_ia according to the page index
801  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
802  * the caller must use lower_ia in a call to notify_change() to perform
803  * the truncation of the lower inode.
804  *
805  * Returns zero on success; non-zero otherwise
806  */
807 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
808                           struct iattr *lower_ia)
809 {
810         int rc = 0;
811         struct inode *inode = dentry->d_inode;
812         struct ecryptfs_crypt_stat *crypt_stat;
813         loff_t i_size = i_size_read(inode);
814         loff_t lower_size_before_truncate;
815         loff_t lower_size_after_truncate;
816
817         if (unlikely((ia->ia_size == i_size))) {
818                 lower_ia->ia_valid &= ~ATTR_SIZE;
819                 return 0;
820         }
821         rc = ecryptfs_get_lower_file(dentry, inode);
822         if (rc)
823                 return rc;
824         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
825         /* Switch on growing or shrinking file */
826         if (ia->ia_size > i_size) {
827                 char zero[] = { 0x00 };
828
829                 lower_ia->ia_valid &= ~ATTR_SIZE;
830                 /* Write a single 0 at the last position of the file;
831                  * this triggers code that will fill in 0's throughout
832                  * the intermediate portion of the previous end of the
833                  * file and the new and of the file */
834                 rc = ecryptfs_write(inode, zero,
835                                     (ia->ia_size - 1), 1);
836         } else { /* ia->ia_size < i_size_read(inode) */
837                 /* We're chopping off all the pages down to the page
838                  * in which ia->ia_size is located. Fill in the end of
839                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
840                  * PAGE_CACHE_SIZE with zeros. */
841                 size_t num_zeros = (PAGE_CACHE_SIZE
842                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
843
844
845                 /*
846                  * XXX(truncate) this should really happen at the begginning
847                  * of ->setattr.  But the code is too messy to that as part
848                  * of a larger patch.  ecryptfs is also totally missing out
849                  * on the inode_change_ok check at the beginning of
850                  * ->setattr while would include this.
851                  */
852                 rc = inode_newsize_ok(inode, ia->ia_size);
853                 if (rc)
854                         goto out;
855
856                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
857                         truncate_setsize(inode, ia->ia_size);
858                         lower_ia->ia_size = ia->ia_size;
859                         lower_ia->ia_valid |= ATTR_SIZE;
860                         goto out;
861                 }
862                 if (num_zeros) {
863                         char *zeros_virt;
864
865                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
866                         if (!zeros_virt) {
867                                 rc = -ENOMEM;
868                                 goto out;
869                         }
870                         rc = ecryptfs_write(inode, zeros_virt,
871                                             ia->ia_size, num_zeros);
872                         kfree(zeros_virt);
873                         if (rc) {
874                                 printk(KERN_ERR "Error attempting to zero out "
875                                        "the remainder of the end page on "
876                                        "reducing truncate; rc = [%d]\n", rc);
877                                 goto out;
878                         }
879                 }
880                 truncate_setsize(inode, ia->ia_size);
881                 rc = ecryptfs_write_inode_size_to_metadata(inode);
882                 if (rc) {
883                         printk(KERN_ERR "Problem with "
884                                "ecryptfs_write_inode_size_to_metadata; "
885                                "rc = [%d]\n", rc);
886                         goto out;
887                 }
888                 /* We are reducing the size of the ecryptfs file, and need to
889                  * know if we need to reduce the size of the lower file. */
890                 lower_size_before_truncate =
891                     upper_size_to_lower_size(crypt_stat, i_size);
892                 lower_size_after_truncate =
893                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
894                 if (lower_size_after_truncate < lower_size_before_truncate) {
895                         lower_ia->ia_size = lower_size_after_truncate;
896                         lower_ia->ia_valid |= ATTR_SIZE;
897                 } else
898                         lower_ia->ia_valid &= ~ATTR_SIZE;
899         }
900 out:
901         ecryptfs_put_lower_file(inode);
902         return rc;
903 }
904
905 /**
906  * ecryptfs_truncate
907  * @dentry: The ecryptfs layer dentry
908  * @new_length: The length to expand the file to
909  *
910  * Simple function that handles the truncation of an eCryptfs inode and
911  * its corresponding lower inode.
912  *
913  * Returns zero on success; non-zero otherwise
914  */
915 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
916 {
917         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
918         struct iattr lower_ia = { .ia_valid = 0 };
919         int rc;
920
921         rc = truncate_upper(dentry, &ia, &lower_ia);
922         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
923                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
924
925                 mutex_lock(&lower_dentry->d_inode->i_mutex);
926                 rc = notify_change(lower_dentry, &lower_ia);
927                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
928         }
929         return rc;
930 }
931
932 static int
933 ecryptfs_permission(struct inode *inode, int mask)
934 {
935         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
936 }
937
938 /**
939  * ecryptfs_setattr
940  * @dentry: dentry handle to the inode to modify
941  * @ia: Structure with flags of what to change and values
942  *
943  * Updates the metadata of an inode. If the update is to the size
944  * i.e. truncation, then ecryptfs_truncate will handle the size modification
945  * of both the ecryptfs inode and the lower inode.
946  *
947  * All other metadata changes will be passed right to the lower filesystem,
948  * and we will just update our inode to look like the lower.
949  */
950 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
951 {
952         int rc = 0;
953         struct dentry *lower_dentry;
954         struct iattr lower_ia;
955         struct inode *inode;
956         struct inode *lower_inode;
957         struct ecryptfs_crypt_stat *crypt_stat;
958
959         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
960         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
961                 ecryptfs_init_crypt_stat(crypt_stat);
962         inode = dentry->d_inode;
963         lower_inode = ecryptfs_inode_to_lower(inode);
964         lower_dentry = ecryptfs_dentry_to_lower(dentry);
965         mutex_lock(&crypt_stat->cs_mutex);
966         if (S_ISDIR(dentry->d_inode->i_mode))
967                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
968         else if (S_ISREG(dentry->d_inode->i_mode)
969                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
970                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
971                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
972
973                 mount_crypt_stat = &ecryptfs_superblock_to_private(
974                         dentry->d_sb)->mount_crypt_stat;
975                 rc = ecryptfs_get_lower_file(dentry, inode);
976                 if (rc) {
977                         mutex_unlock(&crypt_stat->cs_mutex);
978                         goto out;
979                 }
980                 rc = ecryptfs_read_metadata(dentry);
981                 ecryptfs_put_lower_file(inode);
982                 if (rc) {
983                         if (!(mount_crypt_stat->flags
984                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
985                                 rc = -EIO;
986                                 printk(KERN_WARNING "Either the lower file "
987                                        "is not in a valid eCryptfs format, "
988                                        "or the key could not be retrieved. "
989                                        "Plaintext passthrough mode is not "
990                                        "enabled; returning -EIO\n");
991                                 mutex_unlock(&crypt_stat->cs_mutex);
992                                 goto out;
993                         }
994                         rc = 0;
995                         crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
996                                                | ECRYPTFS_ENCRYPTED);
997                 }
998         }
999         mutex_unlock(&crypt_stat->cs_mutex);
1000         if (S_ISREG(inode->i_mode)) {
1001                 rc = filemap_write_and_wait(inode->i_mapping);
1002                 if (rc)
1003                         goto out;
1004                 fsstack_copy_attr_all(inode, lower_inode);
1005         }
1006         memcpy(&lower_ia, ia, sizeof(lower_ia));
1007         if (ia->ia_valid & ATTR_FILE)
1008                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
1009         if (ia->ia_valid & ATTR_SIZE) {
1010                 rc = truncate_upper(dentry, ia, &lower_ia);
1011                 if (rc < 0)
1012                         goto out;
1013         }
1014
1015         /*
1016          * mode change is for clearing setuid/setgid bits. Allow lower fs
1017          * to interpret this in its own way.
1018          */
1019         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
1020                 lower_ia.ia_valid &= ~ATTR_MODE;
1021
1022         mutex_lock(&lower_dentry->d_inode->i_mutex);
1023         rc = notify_change(lower_dentry, &lower_ia);
1024         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1025 out:
1026         fsstack_copy_attr_all(inode, lower_inode);
1027         return rc;
1028 }
1029
1030 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
1031                           struct kstat *stat)
1032 {
1033         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1034         int rc = 0;
1035
1036         mount_crypt_stat = &ecryptfs_superblock_to_private(
1037                                                 dentry->d_sb)->mount_crypt_stat;
1038         generic_fillattr(dentry->d_inode, stat);
1039         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
1040                 char *target;
1041                 size_t targetsiz;
1042
1043                 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
1044                 if (!rc) {
1045                         kfree(target);
1046                         stat->size = targetsiz;
1047                 }
1048         }
1049         return rc;
1050 }
1051
1052 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1053                      struct kstat *stat)
1054 {
1055         struct kstat lower_stat;
1056         int rc;
1057
1058         rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1059                          ecryptfs_dentry_to_lower(dentry), &lower_stat);
1060         if (!rc) {
1061                 fsstack_copy_attr_all(dentry->d_inode,
1062                                       ecryptfs_inode_to_lower(dentry->d_inode));
1063                 generic_fillattr(dentry->d_inode, stat);
1064                 stat->blocks = lower_stat.blocks;
1065         }
1066         return rc;
1067 }
1068
1069 int
1070 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1071                   size_t size, int flags)
1072 {
1073         int rc = 0;
1074         struct dentry *lower_dentry;
1075
1076         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1077         if (!lower_dentry->d_inode->i_op->setxattr) {
1078                 rc = -EOPNOTSUPP;
1079                 goto out;
1080         }
1081
1082         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1083 out:
1084         return rc;
1085 }
1086
1087 ssize_t
1088 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1089                         void *value, size_t size)
1090 {
1091         int rc = 0;
1092
1093         if (!lower_dentry->d_inode->i_op->getxattr) {
1094                 rc = -EOPNOTSUPP;
1095                 goto out;
1096         }
1097         mutex_lock(&lower_dentry->d_inode->i_mutex);
1098         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1099                                                    size);
1100         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1101 out:
1102         return rc;
1103 }
1104
1105 static ssize_t
1106 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1107                   size_t size)
1108 {
1109         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1110                                        value, size);
1111 }
1112
1113 static ssize_t
1114 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1115 {
1116         int rc = 0;
1117         struct dentry *lower_dentry;
1118
1119         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1120         if (!lower_dentry->d_inode->i_op->listxattr) {
1121                 rc = -EOPNOTSUPP;
1122                 goto out;
1123         }
1124         mutex_lock(&lower_dentry->d_inode->i_mutex);
1125         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1126         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1127 out:
1128         return rc;
1129 }
1130
1131 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1132 {
1133         int rc = 0;
1134         struct dentry *lower_dentry;
1135
1136         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1137         if (!lower_dentry->d_inode->i_op->removexattr) {
1138                 rc = -EOPNOTSUPP;
1139                 goto out;
1140         }
1141         mutex_lock(&lower_dentry->d_inode->i_mutex);
1142         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1143         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1144 out:
1145         return rc;
1146 }
1147
1148 const struct inode_operations ecryptfs_symlink_iops = {
1149         .readlink = ecryptfs_readlink,
1150         .follow_link = ecryptfs_follow_link,
1151         .put_link = ecryptfs_put_link,
1152         .permission = ecryptfs_permission,
1153         .setattr = ecryptfs_setattr,
1154         .getattr = ecryptfs_getattr_link,
1155         .setxattr = ecryptfs_setxattr,
1156         .getxattr = ecryptfs_getxattr,
1157         .listxattr = ecryptfs_listxattr,
1158         .removexattr = ecryptfs_removexattr
1159 };
1160
1161 const struct inode_operations ecryptfs_dir_iops = {
1162         .create = ecryptfs_create,
1163         .lookup = ecryptfs_lookup,
1164         .link = ecryptfs_link,
1165         .unlink = ecryptfs_unlink,
1166         .symlink = ecryptfs_symlink,
1167         .mkdir = ecryptfs_mkdir,
1168         .rmdir = ecryptfs_rmdir,
1169         .mknod = ecryptfs_mknod,
1170         .rename = ecryptfs_rename,
1171         .permission = ecryptfs_permission,
1172         .setattr = ecryptfs_setattr,
1173         .setxattr = ecryptfs_setxattr,
1174         .getxattr = ecryptfs_getxattr,
1175         .listxattr = ecryptfs_listxattr,
1176         .removexattr = ecryptfs_removexattr
1177 };
1178
1179 const struct inode_operations ecryptfs_main_iops = {
1180         .permission = ecryptfs_permission,
1181         .setattr = ecryptfs_setattr,
1182         .getattr = ecryptfs_getattr,
1183         .setxattr = ecryptfs_setxattr,
1184         .getxattr = ecryptfs_getxattr,
1185         .listxattr = ecryptfs_listxattr,
1186         .removexattr = ecryptfs_removexattr
1187 };