fc44823fea3a84776b4db3b2ffa87cd890e753cf
[platform/adaptation/renesas_rcar/renesas_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 /**
55  * ecryptfs_create_underlying_file
56  * @lower_dir_inode: inode of the parent in the lower fs of the new file
57  * @dentry: New file's dentry
58  * @mode: The mode of the new file
59  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
60  *
61  * Creates the file in the lower file system.
62  *
63  * Returns zero on success; non-zero on error condition
64  */
65 static int
66 ecryptfs_create_underlying_file(struct inode *lower_dir_inode,
67                                 struct dentry *dentry, int mode,
68                                 struct nameidata *nd)
69 {
70         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
71         struct vfsmount *lower_mnt = ecryptfs_dentry_to_lower_mnt(dentry);
72         struct dentry *dentry_save;
73         struct vfsmount *vfsmount_save;
74         unsigned int flags_save;
75         int rc;
76
77         dentry_save = nd->path.dentry;
78         vfsmount_save = nd->path.mnt;
79         flags_save = nd->flags;
80         nd->path.dentry = lower_dentry;
81         nd->path.mnt = lower_mnt;
82         nd->flags &= ~LOOKUP_OPEN;
83         rc = vfs_create(lower_dir_inode, lower_dentry, mode, nd);
84         nd->path.dentry = dentry_save;
85         nd->path.mnt = vfsmount_save;
86         nd->flags = flags_save;
87         return rc;
88 }
89
90 /**
91  * ecryptfs_do_create
92  * @directory_inode: inode of the new file's dentry's parent in ecryptfs
93  * @ecryptfs_dentry: New file's dentry in ecryptfs
94  * @mode: The mode of the new file
95  * @nd: nameidata of ecryptfs' parent's dentry & vfsmount
96  *
97  * Creates the underlying file and the eCryptfs inode which will link to
98  * it. It will also update the eCryptfs directory inode to mimic the
99  * stat of the lower directory inode.
100  *
101  * Returns zero on success; non-zero on error condition
102  */
103 static int
104 ecryptfs_do_create(struct inode *directory_inode,
105                    struct dentry *ecryptfs_dentry, int mode,
106                    struct nameidata *nd)
107 {
108         int rc;
109         struct dentry *lower_dentry;
110         struct dentry *lower_dir_dentry;
111
112         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
113         lower_dir_dentry = lock_parent(lower_dentry);
114         if (IS_ERR(lower_dir_dentry)) {
115                 ecryptfs_printk(KERN_ERR, "Error locking directory of "
116                                 "dentry\n");
117                 rc = PTR_ERR(lower_dir_dentry);
118                 goto out;
119         }
120         rc = ecryptfs_create_underlying_file(lower_dir_dentry->d_inode,
121                                              ecryptfs_dentry, mode, nd);
122         if (rc) {
123                 printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
124                        "rc = [%d]\n", __func__, rc);
125                 goto out_lock;
126         }
127         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
128                                 directory_inode->i_sb, 0);
129         if (rc) {
130                 ecryptfs_printk(KERN_ERR, "Failure in ecryptfs_interpose\n");
131                 goto out_lock;
132         }
133         fsstack_copy_attr_times(directory_inode, lower_dir_dentry->d_inode);
134         fsstack_copy_inode_size(directory_inode, lower_dir_dentry->d_inode);
135 out_lock:
136         unlock_dir(lower_dir_dentry);
137 out:
138         return rc;
139 }
140
141 /**
142  * grow_file
143  * @ecryptfs_dentry: the eCryptfs dentry
144  *
145  * This is the code which will grow the file to its correct size.
146  */
147 static int grow_file(struct dentry *ecryptfs_dentry)
148 {
149         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
150         char zero_virt[] = { 0x00 };
151         int rc = 0;
152
153         rc = ecryptfs_write(ecryptfs_inode, zero_virt, 0, 1);
154         i_size_write(ecryptfs_inode, 0);
155         rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
156         ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat.flags |=
157                 ECRYPTFS_NEW_FILE;
158         return rc;
159 }
160
161 /**
162  * ecryptfs_initialize_file
163  *
164  * Cause the file to be changed from a basic empty file to an ecryptfs
165  * file with a header and first data page.
166  *
167  * Returns zero on success
168  */
169 static int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry)
170 {
171         struct ecryptfs_crypt_stat *crypt_stat =
172                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
173         int rc = 0;
174
175         if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
176                 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
177                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
178                 goto out;
179         }
180         crypt_stat->flags |= ECRYPTFS_NEW_FILE;
181         ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
182         rc = ecryptfs_new_file_context(ecryptfs_dentry);
183         if (rc) {
184                 ecryptfs_printk(KERN_ERR, "Error creating new file "
185                                 "context; rc = [%d]\n", rc);
186                 goto out;
187         }
188         rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
189         if (rc) {
190                 printk(KERN_ERR "%s: Error attempting to initialize "
191                         "the persistent file for the dentry with name "
192                         "[%s]; rc = [%d]\n", __func__,
193                         ecryptfs_dentry->d_name.name, rc);
194                 goto out;
195         }
196         rc = ecryptfs_write_metadata(ecryptfs_dentry);
197         if (rc) {
198                 printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
199                 goto out;
200         }
201         rc = grow_file(ecryptfs_dentry);
202         if (rc)
203                 printk(KERN_ERR "Error growing file; rc = [%d]\n", rc);
204 out:
205         return rc;
206 }
207
208 /**
209  * ecryptfs_create
210  * @dir: The inode of the directory in which to create the file.
211  * @dentry: The eCryptfs dentry
212  * @mode: The mode of the new file.
213  * @nd: nameidata
214  *
215  * Creates a new file.
216  *
217  * Returns zero on success; non-zero on error condition
218  */
219 static int
220 ecryptfs_create(struct inode *directory_inode, struct dentry *ecryptfs_dentry,
221                 int mode, struct nameidata *nd)
222 {
223         int rc;
224
225         /* ecryptfs_do_create() calls ecryptfs_interpose() */
226         rc = ecryptfs_do_create(directory_inode, ecryptfs_dentry, mode, nd);
227         if (unlikely(rc)) {
228                 ecryptfs_printk(KERN_WARNING, "Failed to create file in"
229                                 "lower filesystem\n");
230                 goto out;
231         }
232         /* At this point, a file exists on "disk"; we need to make sure
233          * that this on disk file is prepared to be an ecryptfs file */
234         rc = ecryptfs_initialize_file(ecryptfs_dentry);
235 out:
236         return rc;
237 }
238
239 /**
240  * ecryptfs_lookup_and_interpose_lower - Perform a lookup
241  */
242 int ecryptfs_lookup_and_interpose_lower(struct dentry *ecryptfs_dentry,
243                                         struct dentry *lower_dentry,
244                                         struct inode *ecryptfs_dir_inode,
245                                         struct nameidata *ecryptfs_nd)
246 {
247         struct dentry *lower_dir_dentry;
248         struct vfsmount *lower_mnt;
249         struct inode *lower_inode;
250         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
251         struct ecryptfs_crypt_stat *crypt_stat;
252         char *page_virt = NULL;
253         u64 file_size;
254         int rc = 0;
255
256         lower_dir_dentry = lower_dentry->d_parent;
257         lower_mnt = mntget(ecryptfs_dentry_to_lower_mnt(
258                                    ecryptfs_dentry->d_parent));
259         lower_inode = lower_dentry->d_inode;
260         fsstack_copy_attr_atime(ecryptfs_dir_inode, lower_dir_dentry->d_inode);
261         BUG_ON(!lower_dentry->d_count);
262         ecryptfs_set_dentry_private(ecryptfs_dentry,
263                                     kmem_cache_alloc(ecryptfs_dentry_info_cache,
264                                                      GFP_KERNEL));
265         if (!ecryptfs_dentry_to_private(ecryptfs_dentry)) {
266                 rc = -ENOMEM;
267                 printk(KERN_ERR "%s: Out of memory whilst attempting "
268                        "to allocate ecryptfs_dentry_info struct\n",
269                         __func__);
270                 goto out_put;
271         }
272         ecryptfs_set_dentry_lower(ecryptfs_dentry, lower_dentry);
273         ecryptfs_set_dentry_lower_mnt(ecryptfs_dentry, lower_mnt);
274         if (!lower_dentry->d_inode) {
275                 /* We want to add because we couldn't find in lower */
276                 d_add(ecryptfs_dentry, NULL);
277                 goto out;
278         }
279         rc = ecryptfs_interpose(lower_dentry, ecryptfs_dentry,
280                                 ecryptfs_dir_inode->i_sb,
281                                 ECRYPTFS_INTERPOSE_FLAG_D_ADD);
282         if (rc) {
283                 printk(KERN_ERR "%s: Error interposing; rc = [%d]\n",
284                        __func__, rc);
285                 goto out;
286         }
287         if (S_ISDIR(lower_inode->i_mode))
288                 goto out;
289         if (S_ISLNK(lower_inode->i_mode))
290                 goto out;
291         if (special_file(lower_inode->i_mode))
292                 goto out;
293         if (!ecryptfs_nd)
294                 goto out;
295         /* Released in this function */
296         page_virt = kmem_cache_zalloc(ecryptfs_header_cache_2, GFP_USER);
297         if (!page_virt) {
298                 printk(KERN_ERR "%s: Cannot kmem_cache_zalloc() a page\n",
299                        __func__);
300                 rc = -ENOMEM;
301                 goto out;
302         }
303         rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
304         if (rc) {
305                 printk(KERN_ERR "%s: Error attempting to initialize "
306                         "the persistent file for the dentry with name "
307                         "[%s]; rc = [%d]\n", __func__,
308                         ecryptfs_dentry->d_name.name, rc);
309                 goto out_free_kmem;
310         }
311         crypt_stat = &ecryptfs_inode_to_private(
312                                         ecryptfs_dentry->d_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         rc = ecryptfs_read_and_validate_header_region(page_virt,
317                                                       ecryptfs_dentry->d_inode);
318         if (rc) {
319                 memset(page_virt, 0, PAGE_CACHE_SIZE);
320                 rc = ecryptfs_read_and_validate_xattr_region(page_virt,
321                                                              ecryptfs_dentry);
322                 if (rc) {
323                         rc = 0;
324                         goto out_free_kmem;
325                 }
326                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
327         }
328         mount_crypt_stat = &ecryptfs_superblock_to_private(
329                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
330         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
331                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
332                         file_size = (crypt_stat->metadata_size
333                                      + i_size_read(lower_dentry->d_inode));
334                 else
335                         file_size = i_size_read(lower_dentry->d_inode);
336         } else {
337                 file_size = get_unaligned_be64(page_virt);
338         }
339         i_size_write(ecryptfs_dentry->d_inode, (loff_t)file_size);
340 out_free_kmem:
341         kmem_cache_free(ecryptfs_header_cache_2, page_virt);
342         goto out;
343 out_put:
344         dput(lower_dentry);
345         mntput(lower_mnt);
346         d_drop(ecryptfs_dentry);
347 out:
348         return rc;
349 }
350
351 /**
352  * ecryptfs_lookup
353  * @ecryptfs_dir_inode: The eCryptfs directory inode
354  * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
355  * @ecryptfs_nd: nameidata; may be NULL
356  *
357  * Find a file on disk. If the file does not exist, then we'll add it to the
358  * dentry cache and continue on to read it from the disk.
359  */
360 static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
361                                       struct dentry *ecryptfs_dentry,
362                                       struct nameidata *ecryptfs_nd)
363 {
364         char *encrypted_and_encoded_name = NULL;
365         size_t encrypted_and_encoded_name_size;
366         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
367         struct dentry *lower_dir_dentry, *lower_dentry;
368         int rc = 0;
369
370         if ((ecryptfs_dentry->d_name.len == 1
371              && !strcmp(ecryptfs_dentry->d_name.name, "."))
372             || (ecryptfs_dentry->d_name.len == 2
373                 && !strcmp(ecryptfs_dentry->d_name.name, ".."))) {
374                 goto out_d_drop;
375         }
376         lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
377         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
378         lower_dentry = lookup_one_len(ecryptfs_dentry->d_name.name,
379                                       lower_dir_dentry,
380                                       ecryptfs_dentry->d_name.len);
381         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
382         if (IS_ERR(lower_dentry)) {
383                 rc = PTR_ERR(lower_dentry);
384                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
385                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
386                                 encrypted_and_encoded_name);
387                 goto out_d_drop;
388         }
389         if (lower_dentry->d_inode)
390                 goto lookup_and_interpose;
391         mount_crypt_stat = &ecryptfs_superblock_to_private(
392                                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
393         if (!(mount_crypt_stat
394             && (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)))
395                 goto lookup_and_interpose;
396         dput(lower_dentry);
397         rc = ecryptfs_encrypt_and_encode_filename(
398                 &encrypted_and_encoded_name, &encrypted_and_encoded_name_size,
399                 NULL, mount_crypt_stat, ecryptfs_dentry->d_name.name,
400                 ecryptfs_dentry->d_name.len);
401         if (rc) {
402                 printk(KERN_ERR "%s: Error attempting to encrypt and encode "
403                        "filename; rc = [%d]\n", __func__, rc);
404                 goto out_d_drop;
405         }
406         mutex_lock(&lower_dir_dentry->d_inode->i_mutex);
407         lower_dentry = lookup_one_len(encrypted_and_encoded_name,
408                                       lower_dir_dentry,
409                                       encrypted_and_encoded_name_size);
410         mutex_unlock(&lower_dir_dentry->d_inode->i_mutex);
411         if (IS_ERR(lower_dentry)) {
412                 rc = PTR_ERR(lower_dentry);
413                 ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
414                                 "[%d] on lower_dentry = [%s]\n", __func__, rc,
415                                 encrypted_and_encoded_name);
416                 goto out_d_drop;
417         }
418 lookup_and_interpose:
419         rc = ecryptfs_lookup_and_interpose_lower(ecryptfs_dentry, lower_dentry,
420                                                  ecryptfs_dir_inode,
421                                                  ecryptfs_nd);
422         goto out;
423 out_d_drop:
424         d_drop(ecryptfs_dentry);
425 out:
426         kfree(encrypted_and_encoded_name);
427         return ERR_PTR(rc);
428 }
429
430 static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
431                          struct dentry *new_dentry)
432 {
433         struct dentry *lower_old_dentry;
434         struct dentry *lower_new_dentry;
435         struct dentry *lower_dir_dentry;
436         u64 file_size_save;
437         int rc;
438
439         file_size_save = i_size_read(old_dentry->d_inode);
440         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
441         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
442         dget(lower_old_dentry);
443         dget(lower_new_dentry);
444         lower_dir_dentry = lock_parent(lower_new_dentry);
445         rc = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
446                       lower_new_dentry);
447         if (rc || !lower_new_dentry->d_inode)
448                 goto out_lock;
449         rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb, 0);
450         if (rc)
451                 goto out_lock;
452         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
453         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
454         old_dentry->d_inode->i_nlink =
455                 ecryptfs_inode_to_lower(old_dentry->d_inode)->i_nlink;
456         i_size_write(new_dentry->d_inode, file_size_save);
457 out_lock:
458         unlock_dir(lower_dir_dentry);
459         dput(lower_new_dentry);
460         dput(lower_old_dentry);
461         return rc;
462 }
463
464 static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
465 {
466         int rc = 0;
467         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
468         struct inode *lower_dir_inode = ecryptfs_inode_to_lower(dir);
469         struct dentry *lower_dir_dentry;
470
471         dget(lower_dentry);
472         lower_dir_dentry = lock_parent(lower_dentry);
473         rc = vfs_unlink(lower_dir_inode, lower_dentry);
474         if (rc) {
475                 printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
476                 goto out_unlock;
477         }
478         fsstack_copy_attr_times(dir, lower_dir_inode);
479         dentry->d_inode->i_nlink =
480                 ecryptfs_inode_to_lower(dentry->d_inode)->i_nlink;
481         dentry->d_inode->i_ctime = dir->i_ctime;
482         d_drop(dentry);
483 out_unlock:
484         unlock_dir(lower_dir_dentry);
485         dput(lower_dentry);
486         return rc;
487 }
488
489 static int ecryptfs_symlink(struct inode *dir, struct dentry *dentry,
490                             const char *symname)
491 {
492         int rc;
493         struct dentry *lower_dentry;
494         struct dentry *lower_dir_dentry;
495         char *encoded_symname;
496         size_t encoded_symlen;
497         struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
498
499         lower_dentry = ecryptfs_dentry_to_lower(dentry);
500         dget(lower_dentry);
501         lower_dir_dentry = lock_parent(lower_dentry);
502         mount_crypt_stat = &ecryptfs_superblock_to_private(
503                 dir->i_sb)->mount_crypt_stat;
504         rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
505                                                   &encoded_symlen,
506                                                   NULL,
507                                                   mount_crypt_stat, symname,
508                                                   strlen(symname));
509         if (rc)
510                 goto out_lock;
511         rc = vfs_symlink(lower_dir_dentry->d_inode, lower_dentry,
512                          encoded_symname);
513         kfree(encoded_symname);
514         if (rc || !lower_dentry->d_inode)
515                 goto out_lock;
516         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
517         if (rc)
518                 goto out_lock;
519         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
520         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
521 out_lock:
522         unlock_dir(lower_dir_dentry);
523         dput(lower_dentry);
524         if (!dentry->d_inode)
525                 d_drop(dentry);
526         return rc;
527 }
528
529 static int ecryptfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
530 {
531         int rc;
532         struct dentry *lower_dentry;
533         struct dentry *lower_dir_dentry;
534
535         lower_dentry = ecryptfs_dentry_to_lower(dentry);
536         lower_dir_dentry = lock_parent(lower_dentry);
537         rc = vfs_mkdir(lower_dir_dentry->d_inode, lower_dentry, mode);
538         if (rc || !lower_dentry->d_inode)
539                 goto out;
540         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
541         if (rc)
542                 goto out;
543         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
544         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
545         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
546 out:
547         unlock_dir(lower_dir_dentry);
548         if (!dentry->d_inode)
549                 d_drop(dentry);
550         return rc;
551 }
552
553 static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
554 {
555         struct dentry *lower_dentry;
556         struct dentry *lower_dir_dentry;
557         int rc;
558
559         lower_dentry = ecryptfs_dentry_to_lower(dentry);
560         dget(dentry);
561         lower_dir_dentry = lock_parent(lower_dentry);
562         dget(lower_dentry);
563         rc = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
564         dput(lower_dentry);
565         if (!rc)
566                 d_delete(lower_dentry);
567         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
568         dir->i_nlink = lower_dir_dentry->d_inode->i_nlink;
569         unlock_dir(lower_dir_dentry);
570         if (!rc)
571                 d_drop(dentry);
572         dput(dentry);
573         return rc;
574 }
575
576 static int
577 ecryptfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
578 {
579         int rc;
580         struct dentry *lower_dentry;
581         struct dentry *lower_dir_dentry;
582
583         lower_dentry = ecryptfs_dentry_to_lower(dentry);
584         lower_dir_dentry = lock_parent(lower_dentry);
585         rc = vfs_mknod(lower_dir_dentry->d_inode, lower_dentry, mode, dev);
586         if (rc || !lower_dentry->d_inode)
587                 goto out;
588         rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb, 0);
589         if (rc)
590                 goto out;
591         fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
592         fsstack_copy_inode_size(dir, lower_dir_dentry->d_inode);
593 out:
594         unlock_dir(lower_dir_dentry);
595         if (!dentry->d_inode)
596                 d_drop(dentry);
597         return rc;
598 }
599
600 static int
601 ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
602                 struct inode *new_dir, struct dentry *new_dentry)
603 {
604         int rc;
605         struct dentry *lower_old_dentry;
606         struct dentry *lower_new_dentry;
607         struct dentry *lower_old_dir_dentry;
608         struct dentry *lower_new_dir_dentry;
609         struct dentry *trap = NULL;
610
611         lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
612         lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
613         dget(lower_old_dentry);
614         dget(lower_new_dentry);
615         lower_old_dir_dentry = dget_parent(lower_old_dentry);
616         lower_new_dir_dentry = dget_parent(lower_new_dentry);
617         trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
618         /* source should not be ancestor of target */
619         if (trap == lower_old_dentry) {
620                 rc = -EINVAL;
621                 goto out_lock;
622         }
623         /* target should not be ancestor of source */
624         if (trap == lower_new_dentry) {
625                 rc = -ENOTEMPTY;
626                 goto out_lock;
627         }
628         rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
629                         lower_new_dir_dentry->d_inode, lower_new_dentry);
630         if (rc)
631                 goto out_lock;
632         fsstack_copy_attr_all(new_dir, lower_new_dir_dentry->d_inode);
633         if (new_dir != old_dir)
634                 fsstack_copy_attr_all(old_dir, lower_old_dir_dentry->d_inode);
635 out_lock:
636         unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
637         dput(lower_new_dentry->d_parent);
638         dput(lower_old_dentry->d_parent);
639         dput(lower_new_dentry);
640         dput(lower_old_dentry);
641         return rc;
642 }
643
644 static int ecryptfs_readlink_lower(struct dentry *dentry, char **buf,
645                                    size_t *bufsiz)
646 {
647         struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
648         char *lower_buf;
649         size_t lower_bufsiz = PATH_MAX;
650         mm_segment_t old_fs;
651         int rc;
652
653         lower_buf = kmalloc(lower_bufsiz, GFP_KERNEL);
654         if (!lower_buf) {
655                 rc = -ENOMEM;
656                 goto out;
657         }
658         old_fs = get_fs();
659         set_fs(get_ds());
660         rc = lower_dentry->d_inode->i_op->readlink(lower_dentry,
661                                                    (char __user *)lower_buf,
662                                                    lower_bufsiz);
663         set_fs(old_fs);
664         if (rc < 0)
665                 goto out;
666         lower_bufsiz = rc;
667         rc = ecryptfs_decode_and_decrypt_filename(buf, bufsiz, dentry,
668                                                   lower_buf, lower_bufsiz);
669 out:
670         kfree(lower_buf);
671         return rc;
672 }
673
674 static int
675 ecryptfs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
676 {
677         char *kbuf;
678         size_t kbufsiz, copied;
679         int rc;
680
681         rc = ecryptfs_readlink_lower(dentry, &kbuf, &kbufsiz);
682         if (rc)
683                 goto out;
684         copied = min_t(size_t, bufsiz, kbufsiz);
685         rc = copy_to_user(buf, kbuf, copied) ? -EFAULT : copied;
686         kfree(kbuf);
687         fsstack_copy_attr_atime(dentry->d_inode,
688                                 ecryptfs_dentry_to_lower(dentry)->d_inode);
689 out:
690         return rc;
691 }
692
693 static void *ecryptfs_follow_link(struct dentry *dentry, struct nameidata *nd)
694 {
695         char *buf;
696         int len = PAGE_SIZE, rc;
697         mm_segment_t old_fs;
698
699         /* Released in ecryptfs_put_link(); only release here on error */
700         buf = kmalloc(len, GFP_KERNEL);
701         if (!buf) {
702                 buf = ERR_PTR(-ENOMEM);
703                 goto out;
704         }
705         old_fs = get_fs();
706         set_fs(get_ds());
707         rc = dentry->d_inode->i_op->readlink(dentry, (char __user *)buf, len);
708         set_fs(old_fs);
709         if (rc < 0) {
710                 kfree(buf);
711                 buf = ERR_PTR(rc);
712         } else
713                 buf[rc] = '\0';
714 out:
715         nd_set_link(nd, buf);
716         return NULL;
717 }
718
719 static void
720 ecryptfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
721 {
722         char *buf = nd_get_link(nd);
723         if (!IS_ERR(buf)) {
724                 /* Free the char* */
725                 kfree(buf);
726         }
727 }
728
729 /**
730  * upper_size_to_lower_size
731  * @crypt_stat: Crypt_stat associated with file
732  * @upper_size: Size of the upper file
733  *
734  * Calculate the required size of the lower file based on the
735  * specified size of the upper file. This calculation is based on the
736  * number of headers in the underlying file and the extent size.
737  *
738  * Returns Calculated size of the lower file.
739  */
740 static loff_t
741 upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
742                          loff_t upper_size)
743 {
744         loff_t lower_size;
745
746         lower_size = ecryptfs_lower_header_size(crypt_stat);
747         if (upper_size != 0) {
748                 loff_t num_extents;
749
750                 num_extents = upper_size >> crypt_stat->extent_shift;
751                 if (upper_size & ~crypt_stat->extent_mask)
752                         num_extents++;
753                 lower_size += (num_extents * crypt_stat->extent_size);
754         }
755         return lower_size;
756 }
757
758 /**
759  * truncate_upper
760  * @dentry: The ecryptfs layer dentry
761  * @ia: Address of the ecryptfs inode's attributes
762  * @lower_ia: Address of the lower inode's attributes
763  *
764  * Function to handle truncations modifying the size of the file. Note
765  * that the file sizes are interpolated. When expanding, we are simply
766  * writing strings of 0's out. When truncating, we truncate the upper
767  * inode and update the lower_ia according to the page index
768  * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
769  * the caller must use lower_ia in a call to notify_change() to perform
770  * the truncation of the lower inode.
771  *
772  * Returns zero on success; non-zero otherwise
773  */
774 static int truncate_upper(struct dentry *dentry, struct iattr *ia,
775                           struct iattr *lower_ia)
776 {
777         int rc = 0;
778         struct inode *inode = dentry->d_inode;
779         struct ecryptfs_crypt_stat *crypt_stat;
780         loff_t i_size = i_size_read(inode);
781         loff_t lower_size_before_truncate;
782         loff_t lower_size_after_truncate;
783
784         if (unlikely((ia->ia_size == i_size))) {
785                 lower_ia->ia_valid &= ~ATTR_SIZE;
786                 goto out;
787         }
788         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
789         /* Switch on growing or shrinking file */
790         if (ia->ia_size > i_size) {
791                 char zero[] = { 0x00 };
792
793                 lower_ia->ia_valid &= ~ATTR_SIZE;
794                 /* Write a single 0 at the last position of the file;
795                  * this triggers code that will fill in 0's throughout
796                  * the intermediate portion of the previous end of the
797                  * file and the new and of the file */
798                 rc = ecryptfs_write(inode, zero,
799                                     (ia->ia_size - 1), 1);
800         } else { /* ia->ia_size < i_size_read(inode) */
801                 /* We're chopping off all the pages down to the page
802                  * in which ia->ia_size is located. Fill in the end of
803                  * that page from (ia->ia_size & ~PAGE_CACHE_MASK) to
804                  * PAGE_CACHE_SIZE with zeros. */
805                 size_t num_zeros = (PAGE_CACHE_SIZE
806                                     - (ia->ia_size & ~PAGE_CACHE_MASK));
807
808
809                 /*
810                  * XXX(truncate) this should really happen at the begginning
811                  * of ->setattr.  But the code is too messy to that as part
812                  * of a larger patch.  ecryptfs is also totally missing out
813                  * on the inode_change_ok check at the beginning of
814                  * ->setattr while would include this.
815                  */
816                 rc = inode_newsize_ok(inode, ia->ia_size);
817                 if (rc)
818                         goto out;
819
820                 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
821                         truncate_setsize(inode, ia->ia_size);
822                         lower_ia->ia_size = ia->ia_size;
823                         lower_ia->ia_valid |= ATTR_SIZE;
824                         goto out;
825                 }
826                 if (num_zeros) {
827                         char *zeros_virt;
828
829                         zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
830                         if (!zeros_virt) {
831                                 rc = -ENOMEM;
832                                 goto out;
833                         }
834                         rc = ecryptfs_write(inode, zeros_virt,
835                                             ia->ia_size, num_zeros);
836                         kfree(zeros_virt);
837                         if (rc) {
838                                 printk(KERN_ERR "Error attempting to zero out "
839                                        "the remainder of the end page on "
840                                        "reducing truncate; rc = [%d]\n", rc);
841                                 goto out;
842                         }
843                 }
844                 truncate_setsize(inode, ia->ia_size);
845                 rc = ecryptfs_write_inode_size_to_metadata(inode);
846                 if (rc) {
847                         printk(KERN_ERR "Problem with "
848                                "ecryptfs_write_inode_size_to_metadata; "
849                                "rc = [%d]\n", rc);
850                         goto out;
851                 }
852                 /* We are reducing the size of the ecryptfs file, and need to
853                  * know if we need to reduce the size of the lower file. */
854                 lower_size_before_truncate =
855                     upper_size_to_lower_size(crypt_stat, i_size);
856                 lower_size_after_truncate =
857                     upper_size_to_lower_size(crypt_stat, ia->ia_size);
858                 if (lower_size_after_truncate < lower_size_before_truncate) {
859                         lower_ia->ia_size = lower_size_after_truncate;
860                         lower_ia->ia_valid |= ATTR_SIZE;
861                 } else
862                         lower_ia->ia_valid &= ~ATTR_SIZE;
863         }
864 out:
865         return rc;
866 }
867
868 /**
869  * ecryptfs_truncate
870  * @dentry: The ecryptfs layer dentry
871  * @new_length: The length to expand the file to
872  *
873  * Simple function that handles the truncation of an eCryptfs inode and
874  * its corresponding lower inode.
875  *
876  * Returns zero on success; non-zero otherwise
877  */
878 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
879 {
880         struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
881         struct iattr lower_ia = { .ia_valid = 0 };
882         int rc;
883
884         rc = truncate_upper(dentry, &ia, &lower_ia);
885         if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
886                 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
887
888                 mutex_lock(&lower_dentry->d_inode->i_mutex);
889                 rc = notify_change(lower_dentry, &lower_ia);
890                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
891         }
892         return rc;
893 }
894
895 static int
896 ecryptfs_permission(struct inode *inode, int mask, unsigned int flags)
897 {
898         if (flags & IPERM_FLAG_RCU)
899                 return -ECHILD;
900         return inode_permission(ecryptfs_inode_to_lower(inode), mask);
901 }
902
903 /**
904  * ecryptfs_setattr
905  * @dentry: dentry handle to the inode to modify
906  * @ia: Structure with flags of what to change and values
907  *
908  * Updates the metadata of an inode. If the update is to the size
909  * i.e. truncation, then ecryptfs_truncate will handle the size modification
910  * of both the ecryptfs inode and the lower inode.
911  *
912  * All other metadata changes will be passed right to the lower filesystem,
913  * and we will just update our inode to look like the lower.
914  */
915 static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia)
916 {
917         int rc = 0;
918         struct dentry *lower_dentry;
919         struct iattr lower_ia;
920         struct inode *inode;
921         struct inode *lower_inode;
922         struct ecryptfs_crypt_stat *crypt_stat;
923
924         crypt_stat = &ecryptfs_inode_to_private(dentry->d_inode)->crypt_stat;
925         if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
926                 ecryptfs_init_crypt_stat(crypt_stat);
927         inode = dentry->d_inode;
928         lower_inode = ecryptfs_inode_to_lower(inode);
929         lower_dentry = ecryptfs_dentry_to_lower(dentry);
930         mutex_lock(&crypt_stat->cs_mutex);
931         if (S_ISDIR(dentry->d_inode->i_mode))
932                 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
933         else if (S_ISREG(dentry->d_inode->i_mode)
934                  && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
935                      || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
936                 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
937
938                 mount_crypt_stat = &ecryptfs_superblock_to_private(
939                         dentry->d_sb)->mount_crypt_stat;
940                 rc = ecryptfs_read_metadata(dentry);
941                 if (rc) {
942                         if (!(mount_crypt_stat->flags
943                               & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
944                                 rc = -EIO;
945                                 printk(KERN_WARNING "Either the lower file "
946                                        "is not in a valid eCryptfs format, "
947                                        "or the key could not be retrieved. "
948                                        "Plaintext passthrough mode is not "
949                                        "enabled; returning -EIO\n");
950                                 mutex_unlock(&crypt_stat->cs_mutex);
951                                 goto out;
952                         }
953                         rc = 0;
954                         crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
955                 }
956         }
957         mutex_unlock(&crypt_stat->cs_mutex);
958         memcpy(&lower_ia, ia, sizeof(lower_ia));
959         if (ia->ia_valid & ATTR_FILE)
960                 lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
961         if (ia->ia_valid & ATTR_SIZE) {
962                 rc = truncate_upper(dentry, ia, &lower_ia);
963                 if (rc < 0)
964                         goto out;
965         }
966
967         /*
968          * mode change is for clearing setuid/setgid bits. Allow lower fs
969          * to interpret this in its own way.
970          */
971         if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
972                 lower_ia.ia_valid &= ~ATTR_MODE;
973
974         mutex_lock(&lower_dentry->d_inode->i_mutex);
975         rc = notify_change(lower_dentry, &lower_ia);
976         mutex_unlock(&lower_dentry->d_inode->i_mutex);
977 out:
978         fsstack_copy_attr_all(inode, lower_inode);
979         return rc;
980 }
981
982 int ecryptfs_getattr_link(struct vfsmount *mnt, struct dentry *dentry,
983                           struct kstat *stat)
984 {
985         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
986         int rc = 0;
987
988         mount_crypt_stat = &ecryptfs_superblock_to_private(
989                                                 dentry->d_sb)->mount_crypt_stat;
990         generic_fillattr(dentry->d_inode, stat);
991         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
992                 char *target;
993                 size_t targetsiz;
994
995                 rc = ecryptfs_readlink_lower(dentry, &target, &targetsiz);
996                 if (!rc) {
997                         kfree(target);
998                         stat->size = targetsiz;
999                 }
1000         }
1001         return rc;
1002 }
1003
1004 int ecryptfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
1005                      struct kstat *stat)
1006 {
1007         struct kstat lower_stat;
1008         int rc;
1009
1010         rc = vfs_getattr(ecryptfs_dentry_to_lower_mnt(dentry),
1011                          ecryptfs_dentry_to_lower(dentry), &lower_stat);
1012         if (!rc) {
1013                 generic_fillattr(dentry->d_inode, stat);
1014                 stat->blocks = lower_stat.blocks;
1015         }
1016         return rc;
1017 }
1018
1019 int
1020 ecryptfs_setxattr(struct dentry *dentry, const char *name, const void *value,
1021                   size_t size, int flags)
1022 {
1023         int rc = 0;
1024         struct dentry *lower_dentry;
1025
1026         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1027         if (!lower_dentry->d_inode->i_op->setxattr) {
1028                 rc = -EOPNOTSUPP;
1029                 goto out;
1030         }
1031
1032         rc = vfs_setxattr(lower_dentry, name, value, size, flags);
1033 out:
1034         return rc;
1035 }
1036
1037 ssize_t
1038 ecryptfs_getxattr_lower(struct dentry *lower_dentry, const char *name,
1039                         void *value, size_t size)
1040 {
1041         int rc = 0;
1042
1043         if (!lower_dentry->d_inode->i_op->getxattr) {
1044                 rc = -EOPNOTSUPP;
1045                 goto out;
1046         }
1047         mutex_lock(&lower_dentry->d_inode->i_mutex);
1048         rc = lower_dentry->d_inode->i_op->getxattr(lower_dentry, name, value,
1049                                                    size);
1050         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1051 out:
1052         return rc;
1053 }
1054
1055 static ssize_t
1056 ecryptfs_getxattr(struct dentry *dentry, const char *name, void *value,
1057                   size_t size)
1058 {
1059         return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), name,
1060                                        value, size);
1061 }
1062
1063 static ssize_t
1064 ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
1065 {
1066         int rc = 0;
1067         struct dentry *lower_dentry;
1068
1069         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1070         if (!lower_dentry->d_inode->i_op->listxattr) {
1071                 rc = -EOPNOTSUPP;
1072                 goto out;
1073         }
1074         mutex_lock(&lower_dentry->d_inode->i_mutex);
1075         rc = lower_dentry->d_inode->i_op->listxattr(lower_dentry, list, size);
1076         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1077 out:
1078         return rc;
1079 }
1080
1081 static int ecryptfs_removexattr(struct dentry *dentry, const char *name)
1082 {
1083         int rc = 0;
1084         struct dentry *lower_dentry;
1085
1086         lower_dentry = ecryptfs_dentry_to_lower(dentry);
1087         if (!lower_dentry->d_inode->i_op->removexattr) {
1088                 rc = -EOPNOTSUPP;
1089                 goto out;
1090         }
1091         mutex_lock(&lower_dentry->d_inode->i_mutex);
1092         rc = lower_dentry->d_inode->i_op->removexattr(lower_dentry, name);
1093         mutex_unlock(&lower_dentry->d_inode->i_mutex);
1094 out:
1095         return rc;
1096 }
1097
1098 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode)
1099 {
1100         if ((ecryptfs_inode_to_lower(inode)
1101              == (struct inode *)candidate_lower_inode))
1102                 return 1;
1103         else
1104                 return 0;
1105 }
1106
1107 int ecryptfs_inode_set(struct inode *inode, void *lower_inode)
1108 {
1109         ecryptfs_init_inode(inode, (struct inode *)lower_inode);
1110         return 0;
1111 }
1112
1113 const struct inode_operations ecryptfs_symlink_iops = {
1114         .readlink = ecryptfs_readlink,
1115         .follow_link = ecryptfs_follow_link,
1116         .put_link = ecryptfs_put_link,
1117         .permission = ecryptfs_permission,
1118         .setattr = ecryptfs_setattr,
1119         .getattr = ecryptfs_getattr_link,
1120         .setxattr = ecryptfs_setxattr,
1121         .getxattr = ecryptfs_getxattr,
1122         .listxattr = ecryptfs_listxattr,
1123         .removexattr = ecryptfs_removexattr
1124 };
1125
1126 const struct inode_operations ecryptfs_dir_iops = {
1127         .create = ecryptfs_create,
1128         .lookup = ecryptfs_lookup,
1129         .link = ecryptfs_link,
1130         .unlink = ecryptfs_unlink,
1131         .symlink = ecryptfs_symlink,
1132         .mkdir = ecryptfs_mkdir,
1133         .rmdir = ecryptfs_rmdir,
1134         .mknod = ecryptfs_mknod,
1135         .rename = ecryptfs_rename,
1136         .permission = ecryptfs_permission,
1137         .setattr = ecryptfs_setattr,
1138         .setxattr = ecryptfs_setxattr,
1139         .getxattr = ecryptfs_getxattr,
1140         .listxattr = ecryptfs_listxattr,
1141         .removexattr = ecryptfs_removexattr
1142 };
1143
1144 const struct inode_operations ecryptfs_main_iops = {
1145         .permission = ecryptfs_permission,
1146         .setattr = ecryptfs_setattr,
1147         .getattr = ecryptfs_getattr,
1148         .setxattr = ecryptfs_setxattr,
1149         .getxattr = ecryptfs_getxattr,
1150         .listxattr = ecryptfs_listxattr,
1151         .removexattr = ecryptfs_removexattr
1152 };